Network Working Group R. Housley
Internet-Draft Vigil Security, LLC
Intended status: Standards Track S. Ashmore
Expires: April 9, 2009 National Security Agency
C. Wallace
Cygnacom Solutions
October 6, 2008
Trust Anchor Management Protocol (TAMP)
draft-ietf-pkix-tamp-00
Status of this Memo
By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
This Internet-Draft will expire on April 9, 2009.
Housley, et al. Expires April 9, 2009 [Page 1]
Internet-Draft TAMP October 2008
Abstract
This document describes a transport independent protocol for the
management of trust anchors and community identifiers stored in a
trust anchor store. The protocol makes use of the Cryptographic
Message Syntax (CMS), and a digital signature is used to provide
integrity protection and data origin authentication. The protocol
can be used to manage trust anchor stores containing trust anchors
represented as Certificate, TBSCertificate or TrustAnchorInfo
objects.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
1.2. Trust Anchors . . . . . . . . . . . . . . . . . . . . . . 4
1.2.1. Apex Trust Anchors . . . . . . . . . . . . . . . . . . 5
1.2.2. Management Trust Anchors . . . . . . . . . . . . . . . 6
1.2.3. Identity Trust Anchors . . . . . . . . . . . . . . . . 7
1.3. Architectural Elements . . . . . . . . . . . . . . . . . . 7
1.3.1. Cryptographic Module . . . . . . . . . . . . . . . . . 7
1.3.2. Trust Anchor Store . . . . . . . . . . . . . . . . . . 8
1.3.3. TAMP Processing Dependencies . . . . . . . . . . . . . 8
1.3.4. Application-Specific Protocol Processing . . . . . . . 9
1.4. ASN.1 Encoding . . . . . . . . . . . . . . . . . . . . . . 10
2. Cryptographic Message Syntax Profile . . . . . . . . . . . . . 12
2.1. Content Info . . . . . . . . . . . . . . . . . . . . . . . 13
2.2. SignedData Info . . . . . . . . . . . . . . . . . . . . . 13
2.2.1. SignerInfo . . . . . . . . . . . . . . . . . . . . . . 14
2.2.2. EncapsulatedContentInfo . . . . . . . . . . . . . . . 16
2.2.3. Signed Attributes . . . . . . . . . . . . . . . . . . 16
2.2.4. Unsigned Attributes . . . . . . . . . . . . . . . . . 18
3. Trust Anchor Formats . . . . . . . . . . . . . . . . . . . . . 20
4. Trust Anchor Management Protocol Messages . . . . . . . . . . 21
4.1. TAMP Status Query . . . . . . . . . . . . . . . . . . . . 22
4.2. TAMP Status Query Response . . . . . . . . . . . . . . . . 26
4.3. Trust Anchor Update . . . . . . . . . . . . . . . . . . . 28
4.4. Trust Anchor Update Confirm . . . . . . . . . . . . . . . 34
4.5. Apex Trust Anchor Update . . . . . . . . . . . . . . . . . 36
4.6. Apex Trust Anchor Update Confirm . . . . . . . . . . . . . 39
4.7. Community Update . . . . . . . . . . . . . . . . . . . . . 41
4.8. Community Update Confirm . . . . . . . . . . . . . . . . . 43
4.9. Sequence Number Adjust . . . . . . . . . . . . . . . . . . 45
4.10. Sequence Number Adjust Confirm . . . . . . . . . . . . . . 46
4.11. TAMP Error . . . . . . . . . . . . . . . . . . . . . . . . 47
5. Status Codes . . . . . . . . . . . . . . . . . . . . . . . . . 49
6. Sequence Number Processing . . . . . . . . . . . . . . . . . . 54
Housley, et al. Expires April 9, 2009 [Page 2]
Internet-Draft TAMP October 2008
7. Subordination Processing . . . . . . . . . . . . . . . . . . . 56
8. Implementation Considerations . . . . . . . . . . . . . . . . 59
9. Apex trust anchor info certificate extension . . . . . . . . . 60
10. Security Considerations . . . . . . . . . . . . . . . . . . . 61
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 64
12. References . . . . . . . . . . . . . . . . . . . . . . . . . . 65
12.1. Normative References . . . . . . . . . . . . . . . . . . . 65
12.2. Informative References . . . . . . . . . . . . . . . . . . 65
Appendix A. ASN.1 Modules . . . . . . . . . . . . . . . . . . . . 67
A.1. ASN.1 Module Using 1993 Syntax . . . . . . . . . . . . . . 67
A.2. ASN.1 Module Using 1988 Syntax . . . . . . . . . . . . . . 76
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 84
Intellectual Property and Copyright Statements . . . . . . . . . . 85
Housley, et al. Expires April 9, 2009 [Page 3]
Internet-Draft TAMP October 2008
1. Introduction
This document describes the Trust Anchor Management Protocol (TAMP).
TAMP may be used to manage the trust anchors and community
identifiers in any device that uses digital signatures; however, this
specification was written with the requirements of cryptographic
modules in mind. For example, TAMP can support signed firmware
packages [RFC4108], where the trust anchor public key can be used to
validate digital signatures on firmware packages or validate the
X.509 certification path [RFC5280][X.509] of the firmware package
signer.
Most TAMP messages are digitally signed to provide integrity
protection and data origin authentication. Both signed and unsigned
TAMP messages employ the Cryptographic Message Syntax (CMS)
[RFC3852]. The CMS is a data protection encapsulation syntax that
makes use of ASN.1 [X.680].
This specification does not provide for confidentiality of TAMP
messages. If confidentiality is required, then the communications
environment that is used to transfer TAMP messages must provide it.
1.1. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
1.2. Trust Anchors
TAMP manages trust anchors. A trust anchor contains a public key
that is used to validate digital signatures. TAMP recognizes three
formats for representing trust anchor information within the protocol
itself: Certificate [RFC5280], TBSCertificate [RFC5280] and
TrustAnchorInfo [TAF].
All trust anchors are distinguished by the public key, and all trust
anchors consist of the following components:
o A public key signature algorithm identifier and associated public
key, which MAY include parameters
o A public key identifier
Other information may appear in a trust anchor, including
certification path processing controls and a human readable name.
TAMP recognizes three types of trust anchors based on functionality:
Housley, et al. Expires April 9, 2009 [Page 4]
Internet-Draft TAMP October 2008
apex trust anchors, management trust anchors, and identity trust
anchors.
In addition to the information described above, apex trust anchors
and management trust anchors that issue TAMP messages also include a
sequence number for replay detection.
The public key is used to name a trust anchor, and the public key
identifier is used to identify the trust anchor as the signer. This
public key identifier can be stored with the trust anchor, or in most
public key identifier assignment methods, it can be computed from the
public key whenever needed.
A trust anchor public key can be used in two different ways to
support digital signature validation. In the first approach, the
trust anchor public key is used directly to validate the digital
signature. In the second approach, the trust anchor public key is
used to validate an X.509 certification path, and then the subject
public key in the final certificate in the certification path is used
to validate the digital signature. When the second approach is
employed, the certified public key can be used for things other than
digital signature validation; the other possible actions are
constrained by the key usage certificate extension.
TAMP implementations MUST support validation of TAMP messages that
are directly signed by a trust anchor. Support for TAMP messages
validated using an X.509 certificate signed by a trust anchor, or
using longer certification paths, is OPTIONAL. The CMS provides a
location to carry X.509 certificates, and this facility can be used
to transfer certificates to aid in the construction of the
certification path.
1.2.1. Apex Trust Anchors
Within the context of a single trust anchor store, one trust anchor
is superior to all others. This trust anchor is referred to as the
apex trust anchor. This trust anchor represents the ultimate
authority over the trust anchor store. Much of this authority can be
delegated to other trust anchors.
The apex trust anchor private key is expected to be controlled by an
entity with information assurance responsibility for the trust anchor
store. The apex trust anchor is by definition unconstrained and
therefore does not have explicit authorization information associated
with it. In order to make processing of messages as uniform as
possible, the apex has an implicit OID associated with it that
represents the special id-ct-anyContentType value. This OID will be
used as input to processing algorithms to represent the apex trust
Housley, et al. Expires April 9, 2009 [Page 5]
Internet-Draft TAMP October 2008
anchor authorization.
Due to the special nature of the apex trust anchor, TAMP includes
separate facilities to change it. In particular, TAMP includes a
facility to securely replace the apex trust anchor. This action
might be taken for one or more of the following reasons:
o The crypto period for the apex trust anchor public/private key
pair has come to an end
o The apex trust anchor private key is no longer available
o The apex trust anchor public/private key pair needs to be revoked
o The authority has decided to use a different digital signature
algorithm or the same digital signature algorithm with different
parameters, such as a different elliptic curve
o The authority has decided to use a different key size
o The authority has decided to transfer control to another authority
To accommodate these requirements, the apex trust anchor MAY include
two public keys. Whenever the apex trust anchor is updated, both
public keys would be replaced. The first public key, called the
operational public key, is used in the same manner as other trust
anchors. Any type of TAMP message, including an Apex Trust Anchor
Update message, can be validated with the operational public key.
The second public key, called the contingency public key, can only be
used to update the apex trust anchor. The contingency private key
SHOULD be used at only one point in time; it is used only to sign an
Apex Trust Anchor Update message which results in its own replacement
(as well as the replacement of the operational public key). The
contingency public key is distributed in encrypted form. When the
contingency public key is used to validate an Apex Trust Anchor
Update message, the symmetric key needed to decrypt the contingency
public key is provided as part of the signed Apex Trust Anchor Update
message that is to be verified with the contingency public key.
1.2.2. Management Trust Anchors
Management trust anchors are used in the management of cryptographic
modules. For example, the TAMP messages specified in this document
are validated to a management trust anchor. Likewise, a signed
firmware package as specified in [RFC4108] is validated to a
management trust anchor.
Authorization checking is needed for management messages, and these
Housley, et al. Expires April 9, 2009 [Page 6]
Internet-Draft TAMP October 2008
checks are based on the content type of the management message. As a
result, management trust anchors include a list of object identifiers
(OIDs) that name authorized content types along with OPTIONAL
constraints.
1.2.3. Identity Trust Anchors
Identity trust anchors are used to validate certification paths, and
they represent the trust anchor for a public key infrastructure.
They are most often used in the validation of certificates associated
with non-management applications.
1.3. Architectural Elements
TAMP does not assume any particular architecture; however, for TAMP
to be useful in an architecture, it MUST include a cryptographic
module, a trust anchor store, TAMP protocol processing, and other
application-specific protocol processing.
A globally unique algorithm identifier MUST be assigned for each one-
way hash function, digital signature generation/validation algorithm,
and symmetric key unwrapping algorithm that is implemented. To
support CMS, an object identifier (OID) is assigned to name a one-way
hash function, and another OID is assigned to name each combination
of a one-way hash function when used with a digital signature
algorithm. Similarly, certificates associate OIDs assigned to public
key algorithms with subject public keys, and certificates make use of
an OID that names both the one-way hash function and the digital
signature algorithm for the certificate issuer digital signature.
1.3.1. Cryptographic Module
The cryptographic module MUST include the following capabilities:
o The cryptographic module SHOULD support the secure storage of a
digital signature private key to sign TAMP responses and either a
certificate containing the associated public key or a certificate
designator. In the latter case, the certificate is stored
elsewhere but is available to parties that need to validate
cryptographic module digital signatures. The designator is a
public key identifier.
o The cryptographic module MUST support at least one one-way hash
function, one digital signature validation algorithm, one digital
signature generation algorithm, and, if contingency keys are
supported, one symmetric key unwrapping algorithm. If only one
one-way hash function is present, it MUST be consistent with the
digital signature validation and digital signature generation
Housley, et al. Expires April 9, 2009 [Page 7]
Internet-Draft TAMP October 2008
algorithms. If only one digital signature validation algorithm is
present, it must be consistent with the apex trust anchor
operational public key. If only one digital signature generation
algorithm is present, it must be consistent with the cryptographic
module digital signature private key. These algorithms MUST be
available for processing TAMP messages, including the content
types defined in [RFC3852], and for validation of X.509
certification paths.
1.3.2. Trust Anchor Store
The trust anchor store MUST include the following capabilities:
o Each trust anchor store within a family of cryptographic modules
(which are generally produced by the same manufacturer) MUST have
a unique serial number (with respect to other modules within the
same family). The family is represented as an ASN.1 object
identifier (OID), and the unique serial number is represented as a
string of octets.
o Each trust anchor store SHOULD have the capability to securely
store one or more community identifiers. The community identifier
is an OID, and it identifies a collection of cryptographic modules
that can be the target of a single TAMP message or the intended
recipients for a particular management message.
o The trust anchor store MUST support the secure storage of exactly
one apex trust anchor. The trust anchor store SHOULD support the
secure storage of at least one additional trust anchor.
1.3.3. TAMP Processing Dependencies
TAMP processing MUST include the following capabilities:
o TAMP processing MUST have a means of locating an appropriate trust
anchor. Two mechanisms are available. The first mechanism is
based on the public key identifier for digital signature
verification, and the second mechanism is based on the trust
anchor X.500 distinguished name and other X.509 certification path
controls for certificate path discovery and validation. The first
mechanism MUST be supported, but the second mechanism can also be
used.
o TAMP processing MUST be able to invoke the digital signature
validation algorithm using the public key held in secure storage
for trust anchors.
Housley, et al. Expires April 9, 2009 [Page 8]
Internet-Draft TAMP October 2008
o TAMP processing MUST have read and write access to secure storage
for sequence numbers associated with each TAMP message source as
described in Section 6.
o TAMP processing MUST have read and write access to secure storage
for trust anchors in order to update them. Update operations
include adding trust anchors, removing trust anchors, and
modifying trust anchors. Application-specific access controls
MUST be securely stored with each management trust anchor as
described in Section 1.3.4.
o TAMP processing MUST have read access to secure storage for the
community membership list, if any, to determine whether a targeted
message ought to be accepted.
o To implement the OPTIONAL community identifier update feature,
TAMP processing MUST have read and write access to secure storage
for the community membership list.
o To generate signed confirmation messages, TAMP processing MUST be
able to invoke the digital signature generation algorithm using
the cryptographic module digital signature private key, and it
MUST have read access to the cryptographic module certificate or
its designator. TAMP uses X.509 certificates [RFC5280].
o The TAMP processing MUST have read access to the family identifier
and serial number.
1.3.4. Application-Specific Protocol Processing
The apex trust anchor and management trust anchors managed with TAMP
can be used by the TAMP application. Other management applications
MAY make use of all three types of trust anchors, but non-management
applications SHOULD only make use of identity trust anchors.
Applications MUST ensure usage of a trust anchor is consistent with
any constraints associated with the trust anchor. For example, if
name constraints are associated with a trust anchor, certification
paths that start with the trust anchor and contain certificates with
names that violate the name constraints MUST be rejected.
The application-specific protocol processing MUST be provided the
following services:
o The application-specific protocol processing MUST have a means of
locating an appropriate trust anchor. Two mechanisms are
available to applications. The first mechanism is based on the
public key identifier for digital signature verification, and the
second mechanism is based on the trust anchor X.500 distinguished
Housley, et al. Expires April 9, 2009 [Page 9]
Internet-Draft TAMP October 2008
name and other X.509 certification path controls for certificate
path discovery and validation.
o The application-specific protocol processing MUST be able to
invoke the digital signature validation algorithm using the public
key held in secure storage for trust anchors.
o The application-specific protocol processing MUST have read access
to the content types and any associated constraints held in
storage with management trust anchors to make authorization
decisions for that application. The authorization decisions apply
to the management trust anchor as well as any public key that is
validated to the management trust anchor via an X.509
certification path.
o If the application-specific protocol requires digital signatures
on confirmation messages or receipts, then the application-
specific protocol processing MUST be able to invoke the digital
signature generation algorithm with the cryptographic module
digital signature private key and its associated certificate or
certificate designator. Digital signature generation MUST be
controlled in a manner that ensures that the content type of
signed confirmation messages or receipts is appropriate for the
application-specific protocol processing.
o The application-specific protocol processing MUST have read access
to the family identifier, serial number, and community membership
list.
It is expected that application-specific protocol processing will
also include constraints processing. In some applications,
management trust anchors could be authorized for a subset of the
functionality associated with a particular content type.
1.4. ASN.1 Encoding
The CMS uses Abstract Syntax Notation One (ASN.1) [X.680]. ASN.1 is
a formal notation used for describing data protocols, regardless of
the programming language used by the implementation. Encoding rules
describe how the values defined in ASN.1 will be represented for
transmission. The Basic Encoding Rules (BER) [X.690] are the most
widely employed rule set, but they offer more than one way to
represent data structures. For example, definite length encoding and
indefinite length encoding are supported. This flexibility is not
desirable when digital signatures are used. As a result, the
Distinguished Encoding Rules (DER) [X.690] were invented. DER is a
subset of BER that ensures a single way to represent a given value.
For example, DER always employs definite length encoding.
Housley, et al. Expires April 9, 2009 [Page 10]
Internet-Draft TAMP October 2008
Digitally signed structures MUST be encoded with DER. In other
specifications, structures that are not digitally signed do not
require DER, but in this specification, DER is REQUIRED for all
structures. By always using DER, the TAMP processor will have fewer
options to implement.
ASN.1 is used throughout the text of the document for illustrative
purposes. The authoritative source of ASN.1 for the structures
defined in this document is Appendix A.
Housley, et al. Expires April 9, 2009 [Page 11]
Internet-Draft TAMP October 2008
2. Cryptographic Message Syntax Profile
TAMP makes use of signed and unsigned messages. The Cryptographic
Message Syntax (CMS) is used in both cases. A digital signature is
used to protect the message from undetected modification and provide
data origin authentication. TAMP makes no general provision for
encryption of content.
CMS is used to construct a signed TAMP message. The CMS ContentInfo
content type MUST always be present, and it MUST encapsulate the CMS
SignedData content type. The CMS SignedData content type MUST
encapsulate the TAMP message. A unique content type identifier
identifies the particular TAMP message. The CMS encapsulation of a
signed TAMP message is summarized by:
ContentInfo {
contentType id-signedData, -- (1.2.840.113549.1.7.2)
content SignedData
}
SignedData {
version CMSVersion, -- Always set to 3
digestAlgorithms DigestAlgorithmIdentifiers, -- Only one
encapContentInfo EncapsulatedContentInfo,
certificates CertificateSet, -- OPTIONAL signer certificates
crls CertificateRevocationLists, -- OPTIONAL
signerInfos SET OF SignerInfo -- Only one
}
SignerInfo {
version CMSVersion, -- Always set to 3
sid SignerIdentifier,
digestAlgorithm DigestAlgorithmIdentifier,
signedAttrs SignedAttributes,
-- REQUIRED in TAMP messages
signatureAlgorithm SignatureAlgorithmIdentifier,
signature SignatureValue,
unsignedAttrs UnsignedAttributes -- OPTIONAL; may only be
} -- present in Apex Trust
-- Anchor Update messages
EncapsulatedContentInfo {
eContentType OBJECT IDENTIFIER, -- Names TAMP message type
eContent OCTET STRING -- Contains TAMP message
}
Housley, et al. Expires April 9, 2009 [Page 12]
Internet-Draft TAMP October 2008
When a TAMP message is used to update the apex trust anchor, this
same structure is used; however, the digital signature will be
validated with either the apex trust anchor operational public key or
the contingency public key. When the contingency public key is used,
the symmetric key needed to decrypt the previously stored contingency
public key is provided as a contingency-public-key-decrypt-key
unsigned attribute. Section 4.5 of this document describes the Apex
Trust Anchor Update message.
CMS is also used to construct an unsigned TAMP message. The CMS
ContentInfo structure MUST always be present, and it MUST be the
outermost layer of encapsulation. A unique content type identifier
identifies the particular TAMP message. The CMS encapsulation of an
unsigned TAMP message is summarized by:
ContentInfo {
contentType OBJECT IDENTIFIER, -- Names TAMP message type
content OCTET STRING -- Contains TAMP message
}
2.1. Content Info
CMS requires the outer-most encapsulation to be ContentInfo
[RFC3852]. The fields of ContentInfo are used as follows:
o contentType indicates the type of the associated content, and for
TAMP, the encapsulated type is either SignedData or the content
type identifier associated with an unsigned TAMP message. When
the id-signedData (1.2.840.113549.1.7.2) object identifier is
present in this field, then a signed TAMP message is in the
content. Otherwise, an unsigned TAMP message is in the content.
o content holds the content, and for TAMP, the content is either a
SignedData content or an unsigned TAMP message.
2.2. SignedData Info
The SignedData content type [RFC3852] contains the signed TAMP
message and a digital signature value; the SignedData content type
MAY also contain the certificates needed to validate the digital
signature. The fields of SignedData are used as follows:
o version is the syntax version number, and for TAMP, the version
number MUST be set to 3.
Housley, et al. Expires April 9, 2009 [Page 13]
Internet-Draft TAMP October 2008
o digestAlgorithms is a collection of one-way hash function
identifiers, and for TAMP, it contains a single one-way hash
function identifier. The one-way hash function employed by the
TAMP message originator in generating the digital signature MUST
be present.
o encapContentInfo is the signed content, consisting of a content
type identifier and the content itself. The use of the
EncapsulatedContentInfo type is discussed further in Section
2.2.2.
o certificates is an OPTIONAL collection of certificates. It MAY be
omitted, or it MAY include the X.509 certificates needed to
construct the certification path of the TAMP message originator.
For TAMP messages sent to a cryptographic module where an apex
trust anchor or management trust anchor is used directly to
validate the TAMP message digital signature, this field SHOULD be
omitted. When an apex trust anchor or management trust anchor is
used to validate an X.509 certification path [RFC5280], and the
subject public key from the final certificate in the certification
path is used to validate the TAMP message digital signature, the
certificate of the TAMP message originator SHOULD be included, and
additional certificates to support certification path construction
MAY be included. For TAMP messages sent by a cryptographic
module, this field SHOULD include only the cryptographic module
certificate or be omitted. A TAMP message recipient MUST NOT
reject a valid TAMP message that contains certificates that are
not needed to validate the digital signature. PKCS#6 extended
certificates [PKCS#6] and attribute certificates (either version 1
or version 2) [RFC3281] MUST NOT be included in the set of
certificates; these certificate formats are not used in TAMP.
Certification Authority (CA) certificates and end entity
certificates MUST conform to the profiles defined in [RFC5280].
o crls is an OPTIONAL collection of certificate revocation lists
(CRLs).
o signerInfos is a collection of per-signer information, and for
TAMP, the collection MUST contain exactly one SignerInfo. The use
of the SignerInfo type is discussed further in Section 2.2.1.
2.2.1. SignerInfo
The TAMP message originator is represented in the SignerInfo type.
The fields of SignerInfo are used as follows:
Housley, et al. Expires April 9, 2009 [Page 14]
Internet-Draft TAMP October 2008
o version is the syntax version number. With TAMP, the version MUST
be set to 3.
o sid identifies the TAMP message originator's public key. The
subjectKeyIdentifier alternative is always used with TAMP, which
identifies the public key directly. When an apex trust anchor
operational public key or a management trust anchor public key is
used directly, this identifier is the keyId from the associated
TrustAnchorInfo. When the public key is included in an X.509
certificate, this identifier is included in the
subjectKeyIdentifier certificate extension.
o digestAlgorithm identifies the one-way hash function, and any
associated parameters, used by the TAMP message originator. It
MUST contain the one-way hash functions employed by the
originator. This message digest algorithm identifier MUST match
the one carried in the digestAlgorithms field in SignedData. The
message digest algorithm identifier is carried in two places to
facilitate stream processing by the receiver.
o signedAttrs is an OPTIONAL set of attributes that are signed along
with the content. The signedAttrs are OPTIONAL in the CMS, but
signedAttrs is REQUIRED for all signed TAMP messages. The SET OF
Attribute MUST be encoded with the distinguished encoding rules
(DER) [X.690]. Section 2.2.3 of this document lists the signed
attributes that MUST be included in the collection. Other signed
attributes MAY be included, but the cryptographic module MUST
ignore any unrecognized signed attributes.
o signatureAlgorithm identifies the digital signature algorithm, and
any associated parameters, used by the TAMP message originator to
generate the digital signature.
o signature is the digital signature value generated by the TAMP
message originator.
o unsignedAttrs is an OPTIONAL set of attributes that are not
signed. For TAMP, this field is usually omitted. It is present
only in Apex Trust Anchor Update messages that are to be validated
using the apex trust anchor contingency public key. In this case,
the SET OF Attribute MUST include the symmetric key needed to
decrypt the contingency public key in the contingency-public-key-
decrypt-key unsigned attribute. Section 2.2.4 of this document
describes this unsigned attribute.
Housley, et al. Expires April 9, 2009 [Page 15]
Internet-Draft TAMP October 2008
2.2.2. EncapsulatedContentInfo
The EncapsulatedContentInfo structure contains the TAMP message. The
fields of EncapsulatedContentInfo are used as follows:
o eContentType is an object identifier that uniquely specifies the
content type, and for TAMP, the value identifies the TAMP message.
The list of TAMP message content types is provided in Section 4.
o eContent is the TAMP message, encoded as an octet string. In
general, the CMS does not require the eContent to be DER-encoded
before constructing the octet string. However, TAMP messages MUST
be DER encoded.
2.2.3. Signed Attributes
The TAMP message originator MUST digitally sign a collection of
attributes along with the TAMP message. Each attribute in the
collection MUST be DER-encoded. The syntax for attributes is defined
in [PKIXASN1]
Each of the attributes used with this CMS profile has a single
attribute value. Even though the syntax is defined as a SET OF
AttributeValue, there MUST be exactly one instance of AttributeValue
present.
The SignedAttributes syntax within SignerInfo is defined as a SET OF
Attribute. The SignedAttributes MUST include only one instance of
any particular attribute. TAMP messages that violate this rule MUST
be rejected as malformed.
The TAMP message originator MUST include the content-type and
message-digest attributes. The TAMP message originator MAY also
include the binary-signing-time or content-hints signed attributes.
The TAMP message originator MAY include any other attribute that it
deems appropriate. The intent is to allow additional signed
attributes to be included if a future need is identified. This does
not cause an interoperability concern because unrecognized signed
attributes MUST be ignored.
The following summarizes the signed attribute requirements for TAMP
messages:
o content-type MUST be supported.
o message-digest MUST be supported.
Housley, et al. Expires April 9, 2009 [Page 16]
Internet-Draft TAMP October 2008
o content-hints MAY be supported. Only present when more than one
layer of encapsulation is employed.
o binary-signing-time MAY be supported. Generally ignored by the
recipient.
o other attributes MAY be supported. Unrecognized attributes MUST
be ignored by the recipient.
2.2.3.1. Content-Type Attribute
The TAMP message originator MUST include a content-type attribute; it
is an object identifier that uniquely specifies the content type.
Section 11.1 of [RFC3852] defines the content-type attribute. For
TAMP, the value identifies the TAMP message. The list of TAMP
message content types and their identifiers is provided in Section 4.
A content-type attribute MUST contain the same object identifier as
the content type contained in the EncapsulatedContentInfo.
2.2.3.2. Message-Digest Attribute
The TAMP message originator MUST include a message-digest attribute,
having as its value the output of a one-way hash function computed on
the TAMP message that is being signed. Section 11.2 of [RFC3852]
defines the message-digest attribute.
2.2.3.3. Content-Hints Attribute
Many applications find it useful to have information that describes
the innermost content when multiple layers of encapsulation have been
applied. Since this version of TAMP only has one layer of
encapsulation, the encapContentInfo provides the content type of the
innermost content. To accommodate future versions of TAMP that might
include additional layers of encapsulation, the content-hints
attribute MUST be included in every instance of SignedData that does
not directly encapsulate a TAMP message. Section 2.9 of [RFC2634]
defines the content-hints attribute.
The content-hints attribute contains two fields: contentDescription
and contentType. The contentType field MUST be present, and the
contentDescription field MAY be present. The fields of the content-
hints attribute are used as follows:
o contentDescription is OPTIONAL. The TAMP message signer MAY
provide a brief description of the purpose of the TAMP message.
The text is intended for human consumption, not machine
processing. The text is encoded in UTF-8 [RFC3629], which
Housley, et al. Expires April 9, 2009 [Page 17]
Internet-Draft TAMP October 2008
accommodates most of the world's writing systems. The
implementation MUST provide the capability to constrain the
character set.
o contentType is mandatory. This field indicates the content type
that will be discovered when CMS protection content types are
removed.
2.2.3.4. Binary-Signing-Time Attribute
The TAMP message originator MAY include a binary-signing-time
attribute, specifying the time at which the digital signature was
applied to the TAMP message. The binary-signing-time attribute is
defined in [RFC4049].
No processing of the binary-signing-time attribute is REQUIRED of a
TAMP message recipient; however, the binary-signing-time attribute
MAY be included by the TAMP message originator as a form of message
identifier.
2.2.4. Unsigned Attributes
For TAMP, unsigned attributes are usually omitted. An unsigned
attribute is present only in Apex Trust Anchor Update messages that
are to be validated by the apex trust anchor contingency public key.
In this case, the symmetric key to decrypt the previous contingency
public key is provided in the contingency-public-key-decrypt-key
unsigned attribute. This attribute MUST be supported, and it is
described in Section 2.2.4.1.
The TAMP message originator SHOULD NOT include other unsigned
attributes, and the cryptographic module MUST ignore unrecognized
unsigned attributes.
The UnsignedAttributes syntax within SignerInfo is defined as a SET
OF Attribute. The UnsignedAttributes MUST include only one instance
of any particular attribute. TAMP messages that violate this rule
MUST be rejected as malformed.
2.2.4.1. Contingency Public Key Decrypt Key Attribute
The contingency-public-key-decrypt-key attribute provides the
plaintext symmetric key needed to decrypt the previously distributed
apex trust anchor contingency public key. The symmetric key MUST be
useable with the symmetric algorithm used to previously encrypt the
contingency public key.
The contingency-public-key-decrypt-key attribute has the following
Housley, et al. Expires April 9, 2009 [Page 18]
Internet-Draft TAMP October 2008
syntax:
contingency-public-key-decrypt-key ATTRIBUTE ::= {
WITH SYNTAX PlaintextSymmetricKey
SINGLE VALUE TRUE
ID id-aa-TAMP-contingencyPublicKeyDecryptKey }
id-aa-TAMP-contingencyPublicKeyDecryptKey
OBJECT IDENTIFIER ::= { id-attributes 63 }
PlaintextSymmetricKey ::= OCTET STRING
Housley, et al. Expires April 9, 2009 [Page 19]
Internet-Draft TAMP October 2008
3. Trust Anchor Formats
TAMP recognizes three formats for representing trust anchor
information within the protocol itself: Certificate [RFC5280],
TBSCertificate [RFC5280] and TrustAnchorInfo [TAF]. The
TrustAnchorChoice structure is used to select one of these options.
TrustAnchorChoice ::= CHOICE {
certificate [0] EXPLICIT Certificate,
tbsCert [1] EXPLICIT TBSCertificate,
taInfo [2] EXPLICIT TrustAnchorInfo }
The Certificate structure is commonly used to represent trust
anchors. Certificates include a signature, which removes the ability
for relying parties to customize the information within the structure
itself. TBSCertificate contains all of the information of the
Certificate structure except for the signature, enabling tailoring of
the information. TrustAnchorInfo is intended to serve as a
minimalist representation of trust anchor information for scenarios
where storage or bandwidth is highly constrained.
Implementations are not required to support all three options. The
unsupportedTrustAnchorFormat error code should be indicated when
generating a TAMPError due to receipt of an unsupported trust anchor
format.
Housley, et al. Expires April 9, 2009 [Page 20]
Internet-Draft TAMP October 2008
4. Trust Anchor Management Protocol Messages
TAMP makes use of signed and unsigned messages. The CMS is used in
both cases. An object identifier is assigned to each TAMP message
type, and this object identifier is used as a content type in the
CMS.
TAMP specifies eleven message types. The following provides the
content type identifier for each TAMP message type, and it indicates
whether a digital signature is REQUIRED. If the following indicates
that the TAMP message MUST be signed, then implementations MUST
reject a message of that type that is not signed.
o The TAMP Status Query message MUST be signed. It uses the
following object identifier: { id-tamp 1 }.
o The TAMP Status Response message SHOULD be signed. It uses the
following object identifier: { id-tamp 2 }.
o The Trust Anchor Update message MUST be signed. It uses the
following object identifier: { id-tamp 3 }.
o The Trust Anchor Update Confirm message SHOULD be signed. It uses
the following object identifier: { id-tamp 4 }.
o The Apex Trust Anchor Update message MUST be signed. It uses the
following object identifier: { id-tamp 5 }.
o The Apex Trust Anchor Update Confirm message SHOULD be signed. It
uses the following object identifier: { id-tamp 6 }.
o The Community Update message MUST be signed. It uses the
following object identifier: { id-tamp 7 }.
o The Community Update Confirm message SHOULD be signed. It uses
the following object identifier: { id-tamp 8 }.
o The Sequence Number Adjust MUST be signed. It uses the following
object identifier: { id-tamp 10 }.
o The Sequence Number Adjust Confirm message SHOULD be signed. It
uses the following object identifier: { id-tamp 11 }.
o The TAMP Error message SHOULD be signed. It uses the following
object identifier: { id-tamp 9 }.
Support for TrustAnchorUpdate messages is REQUIRED. Support for all
other message formats is RECOMMENDED.
Housley, et al. Expires April 9, 2009 [Page 21]
Internet-Draft TAMP October 2008
A typical interaction between a trust anchor manager and a
cryptographic module will follow the message flow shown in Figure
4-1. Figure 4-1 does not illustrate a flow where an error occurs.
+---------+ +----------+
| | Trust Anchor Status Query | |
| |------------------------------->| |
| | | |
| | Trust Anchor Status Response | |
| Trust |<-------------------------------| Crypto |
| Anchor | | Module |
| Manager | Trust Anchor Update | |
| |------------------------------->| |
| | | |
| | Trust Anchor Update Confirm | |
| |<-------------------------------| |
| | | |
+---------+ +----------+
Figure 4-1: Typical TAMP Message Flow
Each TAMP query and update message include an indication of the type
of response that is desired. The response can either be terse or
verbose. All trust anchor stores SHOULD support both the terse and
verbose responses.
Trust anchor stores SHOULD be able to process and properly act upon
the valid payload of the TAMP Status Query message, the Trust Anchor
Update message, the Apex Trust Anchor Update message, and the
Sequence Number Adjust message. TAMP implementations MAY also
process and act upon the valid payload of the Community Update
message.
TAMP implementations SHOULD support generation of the TAMP Status
Response message, the Trust Anchor Update Confirm message, the Apex
Trust Anchor Update Confirm message, the Sequence Number Adjust
Confirm message, and the TAMP Error message. If a cryptographic
module supports the Community Update message, then the cryptographic
module SHOULD also support generation of the Community Update Confirm
message.
4.1. TAMP Status Query
The TAMP Status Query message is used to request information about
the trust anchors that are currently installed in a cryptographic
module, and for the list of communities to which the cryptographic
Housley, et al. Expires April 9, 2009 [Page 22]
Internet-Draft TAMP October 2008
module belongs. The TAMP Status Query message MUST be signed. For
the query message to be valid, the cryptographic module MUST be an
intended recipient of the query, the sequence number checking
described in Section 6 MUST be successful when the TAMP message
signer is a trust anchor, and the digital signature MUST be validated
by the apex trust anchor operational public key, a management trust
anchor authorized for the id-ct-TAMP-statusQuery content type, or via
an authorized X.509 certification path originating with such a trust
anchor.
If the digital signature on the TAMP Status Query message is valid,
sequence number checking is successful, the signer is authorized for
the id-ct-TAMP-statusQuery content type, and the cryptographic module
is an intended recipient of the TAMP message, then a TAMP Status
Response message SHOULD be returned. If a TAMP Status Response
message is not returned, then a TAMP Error message SHOULD be
returned.
The TAMP Status Query content type has the following syntax:
Housley, et al. Expires April 9, 2009 [Page 23]
Internet-Draft TAMP October 2008
PKCS7-CONTENT-TYPE ::= TYPE-IDENTIFIER
tamp-status-query PKCS7-CONTENT-TYPE ::=
{ TAMPStatusQuery IDENTIFIED BY id-ct-TAMP-statusQuery }
id-ct-TAMP-statusQuery OBJECT IDENTIFIER ::= { id-tamp 1 }
TAMPStatusQuery ::= SEQUENCE {
Version [0] TAMPVersion DEFAULT v2,
terse [1] TerseOrVerbose DEFAULT verbose,
query TAMPMsgRef }
TerseOrVerbose ::= ENUMERATED { terse(1), verbose(2) }
TAMPMsgRef ::= SEQUENCE {
target TargetIdentifier,
seqNum SeqNumber }
TargetIdentifier ::= CHOICE {
hwModules [1] HardwareModuleIdentifierList,
communities [2] CommunityIdentifierList,
allModules [3] NULL }
HardwareModuleIdentifierList ::= SEQUENCE SIZE (1..MAX) OF
HardwareModules
HardwareModules ::= SEQUENCE {
hwType OBJECT IDENTIFIER,
hwSerialEntries SEQUENCE SIZE (1..MAX) OF HardwareSerialEntry }
HardwareSerialEntry ::= CHOICE {
all NULL,
single OCTET STRING,
block SEQUENCE {
low OCTET STRING,
high OCTET STRING } }
CommunityIdentifierList ::= SEQUENCE SIZE (0..MAX) OF Community
Community ::= OBJECT IDENTIFIER
The fields of TAMPStatusQuery are used as follows:
o version identifies version of TAMP. For this version of the
specification, the default value, v2, MUST be used.
Housley, et al. Expires April 9, 2009 [Page 24]
Internet-Draft TAMP October 2008
o terse indicates the type of response that is desired. A terse
response is indicated by a value of 1, and a verbose response is
indicated by a value of 2, which is omitted during encoding since
it is the default value.
o query contains two items: the target and the seqNum. target
identifies the cryptographic module or collection of cryptographic
modules that are the target of the query message. seqNum is a
single use value that will be used to match the TAMP Status Query
message with the TAMP Status Response message. The sequence
number is also used to detect TAMP message replay. The sequence
number processing described in Section 6 MUST successfully
complete before a response is returned.
The fields of TAMPMsgRef are used as follows:
o target identifies the cryptographic modules or community of
cryptographic modules that are the target of the query. To
identify a cryptographic module, a combination of a cryptographic
type and serial number are used. The cryptographic type is
represented as an ASN.1 object identifier, and the unique serial
number is represented as a string of octets. To facilitate
compact representation of serial numbers, a contiguous block can
be specified by the lowest included serial number and the highest
included serial number. When present, the high and low octet
strings MUST have the same length. The
HardwareModuleIdentifierList sequence MUST NOT contain duplicate
hwType values, so that each member of the sequence names all of
the cryptographic modules of this type. Object identifiers are
also used to identify communities of cryptographic modules. A
sequence of these object identifiers is used if more than one
community is the target of the message. A cryptographic module is
considered a target if it is a member of any of the listed
communities. An explicit NULL value is used to identify all
modules that consider the signer of the TAMP message to be an
authorized source for that message type.
o seqNum contains a single use value that will be used to match the
TAMP Status Query message with the successful TAMP Status Response
message. The sequence number processing described in Section 6
MUST successfully complete before a response is returned.
To determine whether a particular cryptographic module serial number
is considered part of a specified block, all of the following
conditions MUST be met. First, the cryptographic module serial
number MUST be the same length as both the high and low octet
strings. Second, the cryptographic module serial number MUST be
greater than or equal to the low octet string. Third, the
Housley, et al. Expires April 9, 2009 [Page 25]
Internet-Draft TAMP October 2008
cryptographic module serial number MUST be less than or equal to the
high octet string.
One octet string is equal to another if they are of the same length
and are the same at each octet position. An octet string, S1, is
greater than another, S2, where S1 and S2 have the same length, if
and only if S1 and S2 have different octets in one or more positions,
and in the first such position, the octet in S1 is greater than that
in S2, considering the octets as unsigned binary numbers. Note that
these octet string comparison definitions are consistent with those
in clause 6 of [X.690].
4.2. TAMP Status Query Response
The TAMP Status Response message is a reply by a trust anchor store
to a valid TAMP Status Query message. The TAMP Status Response
message provides information about the trust anchors that are
currently installed in the cryptographic module and the list of
communities to which the trust anchor store belongs, if any. The
TAMP Status Response message MAY be signed or unsigned. A TAMP
Status Response message MUST be signed if the implementation is
capable of signing it.
The TAMP Status Response content type has the following syntax:
Housley, et al. Expires April 9, 2009 [Page 26]
Internet-Draft TAMP October 2008
tamp-status-response PKCS7-CONTENT-TYPE ::=
{ TAMPStatusResponse IDENTIFIED BY id-ct-TAMP-statusResponse }
id-ct-TAMP-statusResponse OBJECT IDENTIFIER ::= { id-tamp 2 }
TAMPStatusResponse ::= SEQUENCE {
version [0] TAMPVersion DEFAULT v2,
query TAMPMsgRef,
response StatusResponse }
StatusResponse ::= CHOICE {
terseResponse [0] TerseStatusResponse,
verboseResponse [1] VerboseStatusResponse }
TerseStatusResponse ::= SEQUENCE {
taKeyIds KeyIdentifiers,
communities CommunityIdentifierList OPTIONAL }
KeyIdentifiers ::= SEQUENCE SIZE (1..MAX) OF KeyIdentifier
VerboseStatusResponse ::= SEQUENCE {
taInfo TrustAnchorChoiceList,
continPubKeyDecryptAlg AlgorithmIdentifier OPTIONAL,
communities CommunityIdentifierList OPTIONAL }
TrustAnchorChoiceList ::= SEQUENCE SIZE (1..MAX) OF
TrustAnchorChoiceWithSeqNumber
TrustAnchorChoiceWithSeqNumber ::= SEQUENCE {
ta TrustAnchorChoice,
seqNumber SeqNumber OPTIONAL
-- seqNumber only present when TA is authorized for TAMP
}
The fields of TAMPStatusResponse are used as follows:
o version identifies version of TAMP. For this version of the
specification, the default value, v2, MUST be used.
o query identifies the TAMPStatusQuery to which the cryptographic
module is responding. The query structure repeats the TAMPMsgRef
from the TAMP Status Query message (see Section 4.1). The
sequence number processing described in Section 6 MUST
successfully complete before any response is returned.
Housley, et al. Expires April 9, 2009 [Page 27]
Internet-Draft TAMP October 2008
o response contains either a terse response or a verbose response.
The terse response is represented by TerseStatusResponse, and the
verbose response is represented by VerboseStatusResponse.
The fields of TerseStatusResponse are used as follows:
o taKeyIds contains a sequence of key identifiers. Each trust
anchor contained in the cryptographic module is represented by one
key identifier. The apex trust anchor is represented by the first
key identifier in the sequence, which contains the key identifier
of the operational public key.
o communities is OPTIONAL. When present, it contains a sequence of
object identifiers. Each object identifier names one community to
which this cryptographic module belongs. When the module belongs
to no communities, this field is omitted.
The fields of VerboseStatusResponse are used as follows:
o taInfo contains a sequence of TrustAnchorChoiceWithSeqNumber
structures. One entry in the sequence is provided for each trust
anchor contained in the cryptographic module. The apex trust
anchor is the first trust anchor in the sequence. The
TrustAnchorChoiceWithSeqNumber is used to associate a sequence
number with trust anchors authorized to generate TAMP messages.
o continPubKeyDecryptAlg indicates the decryption algorithm needed
to decrypt the currently installed apex trust anchor contingency
public key, if a contingency key is associated with the apex trust
anchor.
o communities is OPTIONAL. When present, it contains a sequence of
object identifiers. Each object identifier names one community to
which this cryptographic module belongs. When the module belongs
to no communities, this field is omitted.
4.3. Trust Anchor Update
The Trust Anchor Update message is used to add, remove, and change
management and identity trust anchors. The Trust Anchor Update
message cannot be used to update the apex trust anchor. The Trust
Anchor Update message MUST be signed. For a Trust Anchor Update
message to be valid, the cryptographic module MUST be an intended
recipient of the update, the sequence number checking described in
Section 6 MUST be successful when the TAMP message source is a trust
anchor, and the digital signature MUST be validated using the apex
trust anchor operational public key, a management trust anchor
authorized for the id-ct-TAMP-update content type, or via an
Housley, et al. Expires April 9, 2009 [Page 28]
Internet-Draft TAMP October 2008
authorized X.509 certification path originating with such a trust
anchor.
If the digital signature on the Trust Anchor Update message is valid,
sequence number checking is successful, the signer is authorized for
the id-ct-TAMP-update content type, and the cryptographic module is
an intended recipient of the TAMP message, then the cryptographic
module MUST perform the specified updates and return a Trust Anchor
Update Confirm message. If a Trust Anchor Update Confirm message is
not returned, then a TAMP Error message SHOULD be returned.
The Trust Anchor Update content type has the following syntax:
Housley, et al. Expires April 9, 2009 [Page 29]
Internet-Draft TAMP October 2008
tamp-update PKCS7-CONTENT-TYPE ::=
{ TAMPUpdate IDENTIFIED BY id-ct-TAMP-update }
id-ct-TAMP-update OBJECT IDENTIFIER ::= { id-tamp 3 }
TAMPUpdate ::= SEQUENCE {
version [0] TAMPVersion DEFAULT v2,
terse [1] TerseOrVerbose DEFAULT verbose,
msgRef TAMPMsgRef,
updates SEQUENCE SIZE (1..MAX) OF TrustAnchorUpdate }
TrustAnchorUpdate ::= CHOICE {
add [1] TrustAnchorChoiceWithSeqNumber,
remove [2] PublicKeyInfo,
change [3] EXPLICIT TrustAnchorChangeInfoChoice }
TrustAnchorChangeInfoChoice ::= CHOICE {
tbsCertChange [0] TBSCertificateChangeInfo,
taChange [1] TrustAnchorChangeInfo }
TBSCertificateChangeInfo ::= SEQUENCE {
serialNumber CertificateSerialNumber OPTIONAL,
signature AlgorithmIdentifier OPTIONAL,
issuer Name OPTIONAL,
validity Validity OPTIONAL,
subject Name OPTIONAL,
subjectPublicKeyInfo SubjectPublicKeyInfo,
exts [3] EXPLICIT Extensions OPTIONAL }
TrustAnchorChangeInfo ::= SEQUENCE {
pubKey PublicKeyInfo,
keyId KeyIdentifier OPTIONAL,
taType [0] TrustAnchorChangeType OPTIONAL,
taTitle [1] TrustAnchorTitle OPTIONAL,
certPath [2] CertPathControls OPTIONAL,
exts [3] Extensions OPTIONAL}
TrustAnchorChangeType ::= CHOICE {
mgmt [1] MgmtTrustAnchorInfo,
ident [2] NULL }
The fields of TAMPUpdate are used as follows:
Housley, et al. Expires April 9, 2009 [Page 30]
Internet-Draft TAMP October 2008
o version identifies version of TAMP. For this version of the
specification, the default value, v2, MUST be used.
o terse indicates the type of response that is desired. A terse
response is indicated by a value of 1, and a verbose response is
indicated by a value of 2, which is omitted during encoding since
it is the default value.
o msgRef contains two items: the target and the seqNum. target
identifies the cryptographic module or collection of cryptographic
modules that are the target of the update message. The
TargetIdentifier syntax is described in Section 4.1. seqNum is a
single use value that will be used to match the Trust Anchor
Update message with the Trust Anchor Update Confirm message. The
sequence number is also used to detect TAMP message replay. The
sequence number processing described in Section 6 MUST
successfully complete before any of the updates are processed.
o updates contains a sequence of updates, which are used to add,
remove, and change management or identity trust anchors. Each
entry in the sequence represents one of these actions, and is
indicated by an instance of TrustAnchorUpdate. The actions are a
batch of updates that MUST be processed in the order that they
appear, but each of the updates is processed independently. Each
of the updates MUST satisfy the subordination checks described in
Section 7. Even if one or more of the updates fail, then the
remaining updates MUST be processed. These updates MUST NOT make
any changes to the apex trust anchor.
The TrustAnchorUpdate is a choice of three structures, and each
alternative represents one of the three possible actions: add,
remove, and change. A description of the syntax associated with each
of these actions follows:
o add is used to insert a new management or identity trust anchor
into the cryptographic module. The TrustAnchorChoiceWithSeqNumber
structure is used to provide the trusted public key and all of the
information associated with it along with an optional sequence
number. However, the action MUST fail if the subordination checks
described in Section 7 are not satisfied. See Section 3 for a
discussion of the TrustAnchorChoice structure. The apex trust
anchor cannot be introduced into a cryptographic module using this
action; therefore taType MUST NOT use ApexTrustAnchorInfo. The
constraints of the existing trust anchors are unchanged by this
action. An attempt to add a management or identity trust anchor
that is already in place with the same values for every field in
the TrustAnchorChoice structure, except the seqNum field, MUST be
treated as a successful addition. When the seqNum field does not
Housley, et al. Expires April 9, 2009 [Page 31]
Internet-Draft TAMP October 2008
match the most recently stored sequence number, the larger value
MUST be stored by the cryptographic module. An attempt to add a
management or identity trust anchor that is already present with
the same pubKey values, but with different values for any of the
fields in the TrustAnchorChoice structure other than the seqNum
field, MUST result in an error. This means a trust anchor may not
be added twice using different TrustAnchorChoice options. If a
different format is desired, the existing trust anchor must be
removed and the new format added.
o remove is used to delete an existing management or identity trust
anchor from the cryptographic module, including the deletion of
the management trust anchor associated with the TAMP message
signer. However, the action MUST fail if the subordination checks
described in Section 7 are not satisfied. The public key
contained in PublicKeyInfo names the management or identity trust
anchor to be deleted. An attempt to delete a trust anchor that is
not present MUST be treated as a successful deletion. The
constraints of the deleted trust anchor are not distributed to
other trust anchors in any manner. The apex trust anchor cannot
be removed using this action, which ensures that this action
cannot place the cryptographic module in an unrecoverable
configuration.
o change is used to update the information associated with an
existing management or identity trust anchor in the cryptographic
module. The public key contained in the PublicKeyInfo field of
TrustAnchorChangeInfo or in the subjectPublicKeyInfo field of a
TBSCertificateChangeInfo names the to-be-updated trust anchor.
However, the action MUST fail if the subordination checks
described in Section 7 are not satisfied. An attempt to change a
trust anchor that is not present MUST result in a failure with the
trustAnchorNotFound status code. The TrustAnchorChangeInfo
structure is used to provide the revised configuration of the
management or identity trust anchor. If the update fails for any
reason, then the original trust anchor configuration MUST be
preserved. The apex trust anchor information cannot be changed
using this action. Attempts to change a trust anchor added as a
Certificate MUST fail. Attempts to change a trust anchor added as
a TBSCertificate using a TrustAnchorChangeInfo MUST fail.
Attempts to change a trust anchor added as a TrustAnchorInfo using
a TBSCertificateChangeInfo MUST fail. Attempts to add an exts
field to v2 TrustAnchorInfo MUST fail.
The fields of TrustAnchorChangeInfo are used as follows:
Housley, et al. Expires April 9, 2009 [Page 32]
Internet-Draft TAMP October 2008
o pubKey contains the algorithm identifier and the public key of the
management or identity trust anchor. It is used to locate the to-
be-updated trust anchor in the cryptographic module storage.
o keyId is OPTIONAL, and when present, it contains the public key
identifier of the trust anchor public key. If this field is not
present, then the public key identifier remains unchanged. If
this field is present, the provided public key identifier replaces
the previous one.
o taType is OPTIONAL, and when present, it carries information
specific to the management trust anchor using the
MgmtTrustAnchorInfo structure or indicates the trust anchor is an
identity trust anchor. This structure can be used to convert an
identity trust anchor to a management trust anchor or vice versa.
If this structure is not present, then the previous taType is
preserved. The syntax and semantics of MgmtTrustAnchorInfo is
discussed in [TAF]. Each of the updates MUST satisfy the
subordination checks described in Section 7. The tampSeqNum field
has been deprecated and is ignored if present.
o taTitle is OPTIONAL, and when present, it provides a human
readable name for the management or identity trust anchor. When
absent in a change trust anchor update, any title that was
previously associated with the trust anchor is removed.
Similarly, when present in a change trust anchor update, the title
in the message is associated with the trust anchor. If a previous
title was associated with the trust anchor, then the title is
replaced. If a title was not previously associated with the trust
anchor, then the title from the update message is added.
o certPath is OPTIONAL, and when present, it provides the controls
needed to construct and validate an X.509 certification path.
When absent in a change trust anchor update, any controls that
were previously associated with the management or identity trust
anchor are removed, which means that delegation is no longer
permitted. Similarly, when present in a change trust anchor
update, the controls in the message are associated with the
management or identity trust anchor. If previous controls,
including the trust anchor distinguished name, were associated
with the trust anchor, then the controls are replaced, which means
that delegation continues to be supported, but that different
certification paths will be valid. If controls were not
previously associated with the management or identity trust
anchor, then the controls from the update message are added, which
enables delegation. The syntax and semantics of CertPathControls
is discussed in [TAF].
Housley, et al. Expires April 9, 2009 [Page 33]
Internet-Draft TAMP October 2008
o exts is OPTIONAL, and when present, it provides the extensions
values that are associated with the trust anchor. When absent in
a change trust anchor update, any extensions that were previously
associated with the trust anchor are removed. Similarly, when
present in a change trust anchor update, the extensions in the
message are associated with the trust anchor. Any extensions
previously associated with the trust anchor are replaced or
removed.
The fields of TBSCertificateChangeInfo are used to alter the fields
within a TBSCertificate structure. TBSCertificate is described in
[RFC5280]. For all fields except exts, if the field is absent in a
change trust anchor update, then any previous value associated with a
trust anchor is unchanged. For the exts field, if the field is
absent in a change trust anchor update, then any previous value
associated with a trust anchor is removed. For all fields, if the
field is present in a change trust anchor update, then any previous
value associated with a trust anchor is replaced with the value from
the update message.
4.4. Trust Anchor Update Confirm
The Trust Anchor Update Confirm message is a reply by a trust anchor
store to a valid Trust Anchor Update message. The Trust Anchor
Update Confirm message provides success and failure information for
each of the requested updates. The Trust Anchor Update Confirm
message MAY be signed or unsigned. A Trust Anchor Update Confirm
message MUST be signed if the implementation is capable of signing
it.
The Trust Anchor Update Confirm content type has the following
syntax:
Housley, et al. Expires April 9, 2009 [Page 34]
Internet-Draft TAMP October 2008
tamp-update-confirm PKCS7-CONTENT-TYPE ::=
{ TAMPUpdateConfirm IDENTIFIED BY id-ct-TAMP-updateConfirm }
id-ct-TAMP-updateConfirm OBJECT IDENTIFIER ::= { id-tamp 4 }
TAMPUpdateConfirm ::= SEQUENCE {
version [0] TAMPVersion DEFAULT v2,
update TAMPMsgRef,
confirm UpdateConfirm }
UpdateConfirm ::= CHOICE
terseConfirm [0] TerseUpdateConfirm,
verboseConfirm [1] VerboseUpdateConfirm }
TerseUpdateConfirm ::= StatusCodeList
StatusCodeList ::= SEQUENCE SIZE (1..MAX) OF StatusCode
VerboseUpdateConfirm ::= SEQUENCE {
status StatusCodeList,
taInfo TrustAnchorChoiceList }
The fields of TAMPUpdateConfirm are used as follows:
o version identifies version of TAMP. For this version of the
specification, the default value, v2, MUST be used.
o update identifies the TAMPUpdate message to which the
cryptographic module is responding. The update structure repeats
the TAMPMsgRef from the Trust Anchor Update message (see Section
4.3). The sequence number processing described in Section 6 MUST
successfully complete before any of the updates are processed.
o confirm contains either a terse update confirmation or a verbose
update confirmation. The terse update confirmation is represented
by TerseUpdateConfirm, and the verbose response is represented by
VerboseUpdateConfirm.
The TerseUpdateConfirm contains a sequence of status codes, one for
each TrustAnchorUpdate structure in the Trust Anchor Update message.
The status codes appear in the same order as the TrustAnchorUpdate
structures to which they apply, and the number of elements in the
status code list MUST be the same as the number of elements in the
trust anchor update list. Each of the status codes is discussed in
Section 5.
The fields of VerboseUpdateConfirm are used as follows:
Housley, et al. Expires April 9, 2009 [Page 35]
Internet-Draft TAMP October 2008
o status contains a sequence of status codes, one for each
TrustAnchorUpdate structure in the Trust Anchor Update message.
The status codes appear in the same order as the TrustAnchorUpdate
structures to which they apply, and the number of elements in the
status code list MUST be the same as the number of elements in the
trust anchor update list. Each of the status codes is discussed
in Section 5.
o taInfo contains a sequence of TrustAnchorChoiceWithSeqNumber
structures. One entry in the sequence is provided for each trust
anchor contained in the cryptographic module. These represent the
state of the trust anchors after the updates have been processed.
The apex trust anchor is the first trust anchor in the sequence.
The TrustAnchorChoiceWithSeqNumber is used to associate a sequence
number with trust anchors authorized to generate TAMP messages.
4.5. Apex Trust Anchor Update
The Apex Trust Anchor Update message replaces the operational public
key and, optionally, the contingency public key associated with the
apex trust anchor. Each cryptographic module has exactly one apex
trust anchor. Since the apex trust anchor represents the ultimate
authority over the cryptographic module, no constraints are
associated with the apex trust anchor. The public key identifier of
the operational public key is used to identify the apex trust anchor
in subsequent TAMP messages. The digital signature on the Apex Trust
Anchor Update message is validated with either the current
operational public key or the current contingency public key. For
the Apex Trust Anchor Update message that is validated with the
operational public key to be valid, the cryptographic module MUST be
a target of the update, the sequence number MUST be larger than the
most recently stored sequence number for the operational public key,
and the digital signature MUST be validated directly with the
operational public key. That is, no delegation via a certification
path is permitted. For the Apex Trust Anchor Update message that is
validated with the contingency public key to be valid, the
cryptographic module MUST be a target of the update, the provided
decryption key MUST properly decrypt the contingency public key, and
the digital signature MUST be validated directly with the decrypted
contingency public key. Again, no delegation via a certification
path is permitted.
If the Apex Trust Anchor Update message is validated using the
operational public key, then sequence number processing is handled
normally, as described in Section 6. If the Apex Trust Anchor Update
message is validated using the contingency public key, then the
TAMPMsgRef sequence number MUST contain a zero value. A sequence
number for subsequent messages that will be validated with the new
Housley, et al. Expires April 9, 2009 [Page 36]
Internet-Draft TAMP October 2008
operational public key can optionally be provided. If no value is
provided, then the cryptographic module MUST be prepared to accept
any sequence number in the next TAMP message validated with the
newly-installed apex trust anchor operational public key. If the
Apex Trust Anchor Update message is valid and the clearTrustAnchors
flag is set to TRUE, then all of the management and identity trust
anchors stored in the cryptographic module MUST be deleted. That is,
the new apex trust anchor MUST be the only trust anchor remaining in
the cryptographic module. If the Apex Trust Anchor Update message is
valid and the clearCommunities flag is set to TRUE, then all
community identifiers stored in the cryptographic module MUST be
deleted.
The SignedData structure includes a sid value, and it identifies the
apex trust anchor public key that will be used to validate the
digital signature on this TAMP message. The public key identifier
for the operational public key is known in advance, and it is stored
as part of the apex trust anchor. The public key identifier for the
contingency public key is not known in advance; however, the presence
of the unsigned attribute containing the symmetric key needed to
decrypt the contingency public key unambiguously indicates that the
TAMP message signer used the contingency private key to sign the Apex
Trust Anchor Update message.
If the digital signature on the Apex Trust Anchor Update message is
valid using either the apex trust anchor operational public key or
the apex trust anchor contingency public key, sequence number
checking is successful, and the cryptographic module is an intended
recipient of the TAMP message, then the cryptographic module MUST
update the apex trust anchor and return an Apex Trust Anchor Update
Confirm message. If an Apex Trust Anchor Update Confirm message is
not returned, then a TAMP Error message SHOULD be returned. Note
that the sequence number MUST be zero if the Apex Trust Anchor Update
message is validated with the apex trust anchor contingency public
key.
The Apex Trust Anchor Update content type has the following syntax:
Housley, et al. Expires April 9, 2009 [Page 37]
Internet-Draft TAMP October 2008
tamp-apex-update PKCS7-CONTENT-TYPE ::=
{ TAMPApexUpdate IDENTIFIED BY id-ct-TAMP-apexUpdate }
id-ct-TAMP-apexUpdate OBJECT IDENTIFIER ::= { id-tamp 5 }
TAMPApexUpdate ::= SEQUENCE {
version [0] TAMPVersion DEFAULT v2,
terse [1] TerseOrVerbose DEFAULT verbose,
msgRef TAMPMsgRef,
clearTrustAnchors BOOLEAN,
clearCommunities BOOLEAN,
apexTA TrustAnchorChoiceWithSeqNumber }
The fields of TAMPApexUpdate are used as follows:
o version identifies version of TAMP. For this version of the
specification, the default value, v2, MUST be used.
o terse indicates the type of response that is desired. A terse
response is indicated by a value of 1, and a verbose response is
indicated by a value of 2, which is omitted during encoding since
it is the default value.
o msgRef contains two items: the target and the seqNum. target
identifies the cryptographic module or collection of cryptographic
modules that are the target of the Apex Trust Anchor Update
message. The TargetIdentifier syntax as described in Section 4.1
is used. seqNum is a single use value that will be used to match
the Apex Trust Anchor Update message with the Apex Trust Anchor
Update Confirm message. The sequence number is also used to
detect TAMP message replay if the message is validated with the
apex trust anchor operational public key. The sequence number
processing described in Section 6 MUST successfully complete
before any action is taken. However, seqNum MUST contain a zero
value if the message is validated with the apex trust anchor
contingency public key.
o clearTrustAnchors is a Boolean. If the value is set to TRUE, then
all of the management and identity trust anchors stored in the
cryptographic module MUST be deleted, leaving the newly installed
apex trust anchor as the only trust anchor in the cryptographic
module. If the value is set to FALSE, the other trust anchors
MUST NOT be changed.
o clearCommunities is a Boolean. If the value is set to TRUE, then
all of the community identifiers stored in the cryptographic
module MUST be deleted, leaving none. If the value is set to
Housley, et al. Expires April 9, 2009 [Page 38]
Internet-Draft TAMP October 2008
FALSE, the list of community identifiers MUST NOT be changed.
o apexTA provides the information for the replacement apex trust
anchor. The TrustAnchorChoiceWithSeqNumber structure is used to
provide the trusted public key and all of the information
associated with it, including an optional sequence number that may
be used to detect TAMP message replay. Where TrustAnchorInfo is
used, the taType MUST use the apex choice. See [TAF] for a
discussion of the TrustAnchorInfo structure. The pubKey, keyId,
taTitle, certPath and exts fields apply to the operational public
key of the apex trust anchor. Where Certificate or TBSCertificate
is used, the ApexTrustAnchorInfo certificate extension MUST appear
as an extension and the CMSContentConstraints certificate
extension MUST NOT appear, the special content type id-ct-
anyContentType is associated with the apex trust anchor
implicitly. Section 9 describes the ApexTrustAnchorInfo
certificate extension.
4.6. Apex Trust Anchor Update Confirm
The Apex Trust Anchor Update Confirm message is a reply by a
cryptographic module to a valid Apex Trust Anchor Update message.
The Apex Trust Anchor Update Confirm message provides success or
failure information for the apex trust anchor update. The Apex Trust
Anchor Update Confirm message MAY be signed or unsigned. An Apex
Trust Anchor Update Confirm message MUST be signed if the
cryptographic module is capable of signing it.
The Apex Trust Anchor Update Confirm content type has the following
syntax:
Housley, et al. Expires April 9, 2009 [Page 39]
Internet-Draft TAMP October 2008
tamp-apex-update-confirm PKCS7-CONTENT-TYPE ::=
{ TAMPApexUpdateConfirm IDENTIFIED BY
id-ct-TAMP-apexUpdateConfirm }
id-ct-TAMP-apexUpdateConfirm OBJECT IDENTIFIER ::= { id-tamp 6 }
TAMPApexUpdateConfirm ::= SEQUENCE {
version [0] TAMPVersion DEFAULT v2,
apexReplace TAMPMsgRef,
apexConfirm ApexUpdateConfirm }
ApexUpdateConfirm ::= CHOICE {
terseApexConfirm [0] TerseApexUpdateConfirm,
verboseApexConfirm [1] VerboseApexUpdateConfirm }
TerseApexUpdateConfirm ::= StatusCode
VerboseApexUpdateConfirm ::= SEQUENCE {
status StatusCode,
taInfo TrustAnchorChoiceList,
communities CommunityIdentifierList OPTIONAL }
The fields of TAMPApexUpdateConfirm are used as follows:
o version identifies version of TAMP. For this version of the
specification, the default value, v2, MUST be used.
o apexReplace identifies the Apex Trust Anchor Update message to
which the cryptographic module is responding. The apexReplace
structure repeats the TAMPMsgRef from the beginning of the Apex
Trust Anchor Update message (see Section 4.5). When the Apex
Trust Anchor Update message is validated with the operational
public key, the sequence number processing described in Section 6
MUST successfully complete before an Apex Trust Anchor Update
Confirm message is generated. When the Apex Trust Anchor Update
message is validated with the contingency public key, normal
sequence number processing is ignored, but the seqNum MUST be
zero.
o apexConfirm contains either a terse update confirmation or a
verbose update confirmation. The terse update confirmation is
represented by TerseApexUpdateConfirm, and the verbose response is
represented by VerboseApexUpdateConfirm.
The TerseApexUpdateConfirm contains a single status code, indicating
the success or failure of the apex trust anchor update. If the apex
trust anchor update failed, then the status code provides the reason
Housley, et al. Expires April 9, 2009 [Page 40]
Internet-Draft TAMP October 2008
for the failure. Each of the status codes is discussed in Section 5.
The fields of VerboseApexUpdateConfirm are used as follows:
o status contains a single status code, indicating the success or
failure of the apex trust anchor update. If the apex trust anchor
update failed, then the status code provides the reason for the
failure. Each of the status codes is discussed in Section 5.
o taInfo contains a sequence of TrustAnchorChoiceWithSeqNumber
structures. One entry in the sequence is provided for each trust
anchor contained in the cryptographic module. These represent the
state of the trust anchors after the apex trust anchor update has
been processed. See [TAF] for a description of the
TrustAnchorInfo structure. The apex trust anchor is the first
trust anchor in the sequence. The TrustAnchorChoiceWithSeqNumber
is used to associate a sequence number with trust anchors
authorized to generate TAMP messages.
o communities is OPTIONAL. When present, it contains a sequence of
object identifiers. Each object identifier names one community to
which this cryptographic module belongs. When the module belongs
to no communities, this field is omitted.
4.7. Community Update
The cryptographic module maintains a list of identifiers for the
communities of which it is a member. The Community Update message
can be used to remove or add community identifiers from this list.
The Community Update message MUST be signed. For the Community
Update message to be valid, the cryptographic module MUST be a target
of the update, the sequence number checking described in Section 6
MUST be successful when the TAMP message source is a trust anchor,
and the digital signature MUST be validated by the apex trust anchor
operational public key, a management trust anchor authorized for the
id-ct-TAMP-communityUpdate content type, or via an X.509
certification path originating with such a trust anchor.
If the cryptographic module supports the Community Update message,
the digital signature on the Community Update message is valid,
sequence number checking is successful, the signer is authorized for
the id-ct-TAMP-communityUpdate content type, and the cryptographic
module is an intended recipient of the TAMP message, then the
cryptographic module MUST make the specified updates and return a
Community Update Confirm message. If a Community Update Confirm
message is not returned, then, a TAMP Error message SHOULD be
returned.
Housley, et al. Expires April 9, 2009 [Page 41]
Internet-Draft TAMP October 2008
The Community Update message contains a batch of updates, and all of
the updates MUST be accepted for the cryptographic module to return a
successful Community Update Confirm message. The remove updates, if
present, MUST be processed before the add updates. Where remove is
present with an empty list, all community identifiers MUST be
removed. This approach prevents community identifiers that are
intended to be mutually exclusive from being installed by a
successful addition and a failed removal. Where add is present, at
least one community identifier MUST appear in the list.
The Community Update content type has the following syntax:
tamp-community-update PKCS7-CONTENT-TYPE ::=
{ TAMPCommunityUpdate IDENTIFIED BY id-ct-TAMP-communityUpdate }
id-ct-TAMP-communityUpdate OBJECT IDENTIFIER ::= { id-tamp 7 }
TAMPCommunityUpdate ::= SEQUENCE {
version [0] TAMPVersion DEFAULT v2,
terse [1] TerseOrVerbose DEFAULT verbose,
msgRef TAMPMsgRef,
updates CommunityUpdates }
CommunityUpdates ::= SEQUENCE {
remove [1] CommunityIdentifierList OPTIONAL,
add [2] CommunityIdentifierList OPTIONAL }
-- At least one MUST be present
The fields of TAMPCommunityUpdate are used as follows:
o version identifies version of TAMP. For this version of the
specification, the default value, v2, MUST be used.
o terse indicates the type of response that is desired. A terse
response is indicated by a value of 1, and a verbose response is
indicated by a value of 2, which is omitted during encoding since
it is the default value.
o msgRef contains two items: the target and the seqNum. target
identifies the cryptographic module or collection of cryptographic
modules that are the target of the update message. The
TargetIdentifier syntax as described in Section 4.1 is used.
seqNum is a single use value that will be used to match the
Community Update message with the Community Update Confirm
message. The sequence number is also used to detect TAMP message
replay. The sequence number processing described in Section 6
Housley, et al. Expires April 9, 2009 [Page 42]
Internet-Draft TAMP October 2008
MUST successfully complete before any of the updates are
processed.
o updates contains a sequence of community identifiers to be removed
and a sequence of community identifiers to be added. These are
represented by the CommunityUpdates structure.
The CommunityUpdates is a sequence of two OPTIONAL sequences, but at
least one of these sequences MUST be present. The first sequence
contains community identifiers to be removed, and if there are none,
it is absent. The second sequence contains community identifiers to
be added, and if there are none, it is absent. The remove updates,
if present, MUST be processed before the add updates. An error is
generated if any of the requested removals or additions cannot be
accomplished. However, requests to remove community identifiers that
are not present are treated as successful removals. Likewise,
requests to add community identifiers that are already present are
treated as successful additions. If an error is generated, the
cryptographic module community list MUST NOT be changed.
A description of the syntax associated with each of these actions
follows:
o remove is used to remove one, multiple or all community
identifiers from the cryptographic module.
o add is used to insert one or more new community identifiers into
the cryptographic module.
4.8. Community Update Confirm
The Community Update Confirm message is a reply by a cryptographic
module to a valid Community Update message. The Community Update
Confirm message provides success or failure information for the
requested updates. Success is returned only if the whole batch of
updates is successfully processed. If any of the requested updates
cannot be performed, then a failure is indicated, and the set of
community identifiers stored in the cryptographic module is
unchanged. The Community Update Confirm message MAY be signed or
unsigned. A Community Update Confirm message MUST be signed if the
cryptographic module is capable of signing it.
The Community Update Confirm content type has the following syntax:
Housley, et al. Expires April 9, 2009 [Page 43]
Internet-Draft TAMP October 2008
tamp-community-update-confirm PKCS7-CONTENT-TYPE ::=
{ TAMPCommunityUpdateConfirm IDENTIFIED BY
id-ct-TAMP-communityUpdateConfirm }
id-ct-TAMP-communityUpdateConfirm OBJECT IDENTIFIER ::=
{ id-tamp 8 }
TAMPCommunityUpdateConfirm ::= SEQUENCE {
version [0] TAMPVersion DEFAULT v2,
update TAMPMsgRef,
commConfirm CommunityConfirm }
CommunityConfirm ::= CHOICE {
terseCommConfirm [0] TerseCommunityConfirm,
verboseCommConfirm [1] VerboseCommunityConfirm }
TerseCommunityConfirm ::= StatusCode
VerboseCommunityConfirm ::= SEQUENCE {
status StatusCode,
communities CommunityIdentifierList OPTIONAL }
The fields of TAMPCommunityUpdateConfirm are used as follows:
o version identifies version of TAMP. For this version of the
specification, the default value, v2, MUST be used.
o update identifies the Community Update message to which the
cryptographic module is responding. The update structure repeats
the TAMPMsgRef from the Community Update message (see Section
4.7). The sequence number processing described in Section 6 MUST
successfully complete before any of the updates are processed.
o commConfirm contains either a terse community update confirmation
or a verbose community update confirmation. The terse response is
represented by TerseCommunityConfirm, and the verbose response is
represented by VerboseCommunityConfirm.
The TerseCommunityConfirm contains a single status code, indicating
the success or failure of the Community Update message has been
processed. If the community update failed, then the status code
indicates the reason for the failure. Each of the status codes is
discussed in Section 5.
The fields of VerboseCommunityConfirm are used as follows:
Housley, et al. Expires April 9, 2009 [Page 44]
Internet-Draft TAMP October 2008
o status contains a single status code, indicating the success or
failure of the Community Update message has been processed. If
the community update failed, then the status code indicates the
reason for the failure. Each of the status codes is discussed in
Section 5.
o communities is OPTIONAL. When present it contains the sequence of
community identifiers present in the cryptographic module after
the update is processed. When the module belongs to no
communities, this field is omitted.
4.9. Sequence Number Adjust
The cryptographic module maintains the current sequence number for
the apex trust anchor and each management trust anchor. Sequence
number processing is discussed in Section 6. The Sequence Number
Adjust message can be used provide the most recently used sequence
number to one or more cryptographic modules, thereby reducing the
possibility of replay. The Sequence Number Adjust message MUST be
signed. For the Sequence Number Adjust message to be valid, the
cryptographic module MUST be an intended recipient of the Sequence
Number Adjust message, the sequence number MUST be equal to or larger
than the most recently stored sequence number for the originating
trust anchor, and the digital signature MUST be validated by the apex
trust anchor operational public key or a management trust anchor that
is authorized for the id-ct-TAMP-seqNumAdjust content type.
If the digital signature on the Sequence Number Adjust message is
valid, the sequence number is equal to or larger than the most
recently stored sequence number for the originating trust anchor, the
signer is authorized for the id-ct-TAMP-seqNumAdjust content type,
and the cryptographic module is an intended recipient of the TAMP
message, then the cryptographic module MUST update the sequence
number associated with the originating trust anchor and return a
Sequence Number Adjust Confirm message. If a Sequence Number Adjust
Confirm message is not returned, then a TAMP Error message SHOULD be
returned.
The Sequence Number Adjust message contains an adjustment for the
sequence number of the TAMP message signer.
The Sequence Number Adjust content type has the following syntax:
Housley, et al. Expires April 9, 2009 [Page 45]
Internet-Draft TAMP October 2008
tamp-sequence-number-adjust PKCS7-CONTENT-TYPE ::=
{ SequenceNumberAdjust IDENTIFIED BY id-ct-TAMP-seqNumAdjust }
id-ct-TAMP-seqNumAdjust OBJECT IDENTIFIER ::= { id-tamp 10 }
SequenceNumberAdjust ::= SEQUENCE {
Version [0] TAMPVersion DEFAULT v2,
msgRef TAMPMsgRef }
The fields of SequenceNumberAdjust are used as follows:
o version identifies version of TAMP. For this version of the
specification, the default value, v2, MUST be used.
o msgRef contains two items: the target and the seqNum. target
identifies the cryptographic module or collection of cryptographic
modules that are the target of the sequence number adjust message.
The TargetIdentifier syntax as described in Section 4.1 is used.
The allModules target is expected to be used for Sequence Number
Adjust messages. seqNum MUST be equal to or larger than the most
recently stored sequence number for this TAMP message source, and
the value will be used to match the Sequence Number Adjust message
with the Sequence Number Adjust Confirm message. The sequence
number processing described in Section 6 applies, except that the
sequence number in a Sequence Number Adjust message is acceptable
if it matches the most recently stored sequence number for this
TAMP message source. If sequence number checking completes
successfully, then the sequence number is adjusted, otherwise it
remains unchanged.
4.10. Sequence Number Adjust Confirm
The Sequence Number Adjust Confirm message is a reply by a
cryptographic module to a valid Sequence Number Adjust message. The
Sequence Number Adjust Confirm message provides success or failure
information. Success is returned only if the sequence number for the
trust anchor that signed the Sequence Number Adjust message
originator is adjusted. If the sequence number cannot be adjusted,
then a failure is indicated, and the sequence number stored in the
cryptographic module is unchanged. The Sequence Number Adjust
Confirm message MAY be signed or unsigned. A Sequence Number Adjust
Confirm message MUST be signed if the cryptographic module is capable
of signing it.
The Sequence Number Adjust Confirm content type has the following
syntax:
Housley, et al. Expires April 9, 2009 [Page 46]
Internet-Draft TAMP October 2008
tamp-sequence-number-adjust-confirm PKCS7-CONTENT-TYPE ::=
{ SequenceNumberAdjustConfirm IDENTIFIED BY
id-ct-TAMP-seqNumAdjustConfirm }
id-ct-TAMP-seqNumAdjustConfirm OBJECT IDENTIFIER ::=
{ id-tamp 11 }
SequenceNumberAdjustConfirm ::= SEQUENCE {
version [0] TAMPVersion DEFAULT v2,
adjust TAMPMsgRef,
status StatusCode }
The fields of SequenceNumberAdjustConfirm are used as follows:
o version identifies version of TAMP. For this version of the
specification, the default value, v2, MUST be used.
o adjust identifies the Sequence Number Adjust message to which the
cryptographic module is responding. The adjust structure repeats
the TAMPMsgRef from the Sequence Number Adjust message (see
Section 4.9). The sequence number processing described in Section
6 MUST successfully complete to adjust the sequence number
associated with the Sequence Number Adjust message originator.
o status contains a single status code, indicating the success or
failure of the Sequence Number Adjust message processing. If the
adjustment failed, then the status code indicates the reason for
the failure. Each of the status codes is discussed in Section 5.
4.11. TAMP Error
The TAMP Error message is a reply by a cryptographic module to any
invalid TAMP message. The TAMP Error message provides an indication
of the reason for the error. The TAMP Error message MAY be signed or
unsigned. A TAMP Error message MUST be signed if the cryptographic
module is capable of signing it.
The object identifier names the TAMP Error message content:
Housley, et al. Expires April 9, 2009 [Page 47]
Internet-Draft TAMP October 2008
tamp-error PKCS7-CONTENT-TYPE ::=
{ TAMPError IDENTIFIED BY id-ct-TAMP-error }
id-ct-TAMP-error OBJECT IDENTIFIER ::= { id-tamp 9 }
TAMPError ::= SEQUENCE {
version [0] TAMPVersion DEFAULT v2,
msgType OBJECT IDENTIFIER,
status StatusCode,
msgRef TAMPMsgRef OPTIONAL }
The fields of TAMPError are used as follows:
o version identifies version of TAMP. For this version of the
specification, the default value, v2, MUST be used.
o msgType indicates the content type of the TAMP message that caused
the error.
o status contains a status code that indicates the reason for the
error. Each of the status codes is discussed in Section 5.
o msgRef is OPTIONAL, but whenever possible it SHOULD be present.
It identifies the TAMP message that caused the error. It repeats
the target and seqNum from the TAMP message that caused the error
(see Sections 4.1, 4.3, 4.5, 4.7 and 4.9).
Housley, et al. Expires April 9, 2009 [Page 48]
Internet-Draft TAMP October 2008
5. Status Codes
The Trust Anchor Update Confirm, the Apex Trust Anchor Update
Confirm, the Community Update Confirm, the Sequence Number Adjust
Confirm, and the TAMP Error messages include status codes. The
syntax for the status codes is:
StatusCode ::= ENUMERATED {
success (0),
decodeFailure (1),
badContentInfo (2),
badSignedData (3),
badEncapContent (4),
badCertificate (5),
badSignerInfo (6),
badSignedAttrs (7),
badUnsignedAttrs (8),
missingContent (9),
noTrustAnchor (10),
notAuthorized (11),
badDigestAlgorithm (12),
badSignatureAlgorithm (13),
unsupportedKeySize (14),
unsupportedParameters (15),
signatureFailure (16),
insufficientMemory (17),
unsupportedTAMPMsgType (18),
apexTAMPAnchor (19),
improperTAAddition (20),
seqNumFailure (21),
contingencyPublicKeyDecrypt (22),
incorrectTarget (23),
communityUpdateFailed (24),
trustAnchorNotFound (25),
unsupportedTAAlgorithm (26),
unsupportedTAKeySize (27),
unsupportedContinPubKeyDecryptAlg (28),
missingSignature (29),
resourcesBusy (30),
versionNumberMismatch (31),
missingPolicySet (32),
revokedCertificate (33),
unsupportedTrustAnchorFormat (34),
other (127) }
Housley, et al. Expires April 9, 2009 [Page 49]
Internet-Draft TAMP October 2008
The various values of StatusCode are used as follows:
o success is used to indicate that an update, portion of an update,
or adjust was processed successfully.
o decodeFailure is used to indicate that the cryptographic module
was unable to successfully decode the provided message. The
specified content type and the provided content do not match.
o badContentInfo is used to indicate that the ContentInfo syntax is
invalid or that the contentType carried within the ContentInfo is
unknown or unsupported.
o badSignedData is used to indicate that the SignedData syntax is
invalid, the version is unknown or unsupported, or more than one
entry is present in digestAlgorithms.
o badEncapContent is used to indicate that the
EncapsulatedContentInfo syntax is invalid. This error can be
generated due to problems located in SignedData.
o badCertificate is used to indicate that the syntax for one or more
certificates in CertificateSet is invalid.
o badSignerInfo is used to indicate that the SignerInfo syntax is
invalid, or the version is unknown or unsupported.
o badSignedAttrs is used to indicate that the signedAttrs syntax
within SignerInfo is invalid.
o badUnsignedAttrs is used to indicate that the unsignedAttrs within
SignerInfo contains an attribute other than the contingency-
public-key-decrypt-key unsigned attribute, which is the only
unsigned attribute supported by this specification.
o missingContent is used to indicate that the OPTIONAL eContent is
missing in EncapsulatedContentInfo, which is REQUIRED in this
specification. This error can be generated due to problems
located in SignedData.
o noTrustAnchor is used to indicate one of two possible error
situations. In one case, the subjectKeyIdentifier does not
identify the public key of a trust anchor or a certification path
that terminates with an installed trust anchor. In the other
case, the issuerAndSerialNumber is used to identify the TAMP
message signer, which is prohibited by this specification.
Housley, et al. Expires April 9, 2009 [Page 50]
Internet-Draft TAMP October 2008
o notAuthorized is used to indicate one of two possible error
situations. In one case the sid within SignerInfo leads to an
installed trust anchor, but that trust anchor is not an authorized
signer for the received TAMP message content type. Identity trust
anchors are not authorized signers for any of the TAMP message
content types. In the other case, the signer of a Trust Anchor
Update message is not authorized to manage the to-be-updated trust
anchor as determined by a failure of the subordination processing
in Sec. 7.
o badDigestAlgorithm is used to indicate that the digestAlgorithm in
either SignerInfo or SignedData is unknown or unsupported.
o badSignatureAlgorithm is used to indicate that the
signatureAlgorithm in SignerInfo is unknown or unsupported.
o unsupportedKeySize is used to indicate that the signatureAlgorithm
in SignerInfo is known and supported, but the TAMP message digital
signature could not be validated because an unsupported key size
was employed by the signer.
o unsupportedParameters is used to indicate that the
signatureAlgorithm in SignerInfo is known, but the TAMP message
digital signature could not be validated because unsupported
parameters were employed by the signer.
o signatureFailure is used to indicate that the signatureAlgorithm
in SignerInfo is known and supported, but the digital signature in
the signature field within SignerInfo could not be validated.
o insufficientMemory indicates that the update could not be
processed because the cryptographic module did not have sufficient
memory to store the resulting trust anchor configuration or
community identifier.
o unsupportedTAMPMsgType indicates that the TAMP message could not
be processed because the cryptographic module does not support the
provided TAMP message type. This code will be used if the id-ct-
TAMP-communityUpdate content type is provided and the
cryptographic module does not support the Community Update
message. This status code will also be used if the contentType
value within eContentType is not one that is defined in this
specification.
o apexTAMPAnchor indicates that the update could not be processed
because the Trust Anchor Update message tried to remove the apex
trust anchor.
Housley, et al. Expires April 9, 2009 [Page 51]
Internet-Draft TAMP October 2008
o improperTAAddition indicates that a trust anchor update is trying
to add a new trust anchor that may already exist, but some
attributes of the to-be-added trust anchor are being modified in
an improper manner. The desired trust anchor configuration may be
attainable with a change operation instead of an add operation.
o seqNumFailure indicates that the TAMP message could not be
processed because the processing of the sequence number, which is
described in Section 6, resulted in an error.
o contingencyPublicKeyDecrypt indicates that the update could not be
processed because an error occurred while decrypting the
contingency public key.
o incorrectTarget indicates that the query, update, or adjust
message could not be processed because the cryptographic module is
not the intended recipient. The target cryptographic module is
identified in one of two ways. HardwareModules identifies the
cryptographic module by the module type and serial number; in
which case, either one or both of these values does not match the
responding cryptographic module. Alternatively, community
identifies a group of cryptographic modules; in which case, the
responding cryptographic module does not belong to the identified
group.
o communityUpdateFailed indicates that the community update
requested the addition of a community identifier or the removal of
a community identifier, but the request could not be honored.
o trustAnchorNotFound indicates that a change to a trust anchor was
requested, but the referenced trust anchor is not represented in
the cryptographic module.
o unsupportedTAAlgorithm indicates that an update message would
result in the trust anchor with a public key associated with a
digital signature validation algorithm that is not implemented in
the cryptographic module. In addition, this status code is used
if the algorithm is supported, but the parameters associated with
the algorithm are not supported.
o unsupportedTAKeySize indicates that the trust anchor would include
a public key of a size that is not supported.
o unsupportedContinPubKeyDecryptAlg indicates that the decryption
algorithm for the apex trust anchor contingency public key is not
supported.
Housley, et al. Expires April 9, 2009 [Page 52]
Internet-Draft TAMP October 2008
o missingSignature indicates that an unsigned TAMP message was
received, but the received TAMP message type MUST be signed.
o resourcesBusy indicates that the resources necessary to process
the TAMP message are not available at the present time, but the
resources might be available at some point in the future.
o versionNumberMismatch indicates that the version number in a
received TAMP message is not acceptable.
o missingPolicySet indicates that the policyFlags associated with a
trust anchor are set in a fashion that requires the policySet to
be present, but the policySet is missing.
o revokedCertificate indicates that one or more of the certificates
needed to properly process the TAMP message has been revoked.
o unsupportedTrustAnchorFormat indicates that an unsupported trust
anchor format was presented or the version is unknown or
unsupported.
o other indicates that the update could not be processed, but the
reason is not covered by any of the assigned status codes. Use of
this status code SHOULD be avoided.
Housley, et al. Expires April 9, 2009 [Page 53]
Internet-Draft TAMP October 2008
6. Sequence Number Processing
The sequence number processing facilities in TAMP represent a balance
between replay protection, operational considerations, and
cryptographic module memory management. The goal is to provide
replay protection without making TAMP difficult to use, creating an
environment where surprising error conditions occur on a regular
basis, or imposing onerous memory management requirements on
implementations. This balance is achieved by performing sequence
number checking on TAMP messages that are signed directly by a trust
anchor, and skipping these checks whenever the TAMP message
originator is represented by a certificate.
The TAMP Status Query, Trust Anchor Update, Apex Trust Anchor Update,
Community Update, and Sequence Number Adjust messages include a
sequence number. This single-use identifier is used to match a TAMP
message with the response to that TAMP message. When the TAMP
message is signed directly by a trust anchor, the sequence number is
also used to detect TAMP message replay.
To provide replay protection, each TAMP message originator MUST treat
the sequence number as a monotonically increasing non-negative
integer. The sequence number counter is associated with the signing
operation performed by the private key. The cryptographic module
MUST ensure that a newly received TAMP message that is validated
directly by a trust anchor public key contains a sequence number that
is greater than the most recent successfully processed TAMP message
from that originator. Note that the Sequence Number Adjust message
is considered valid if the sequence number is greater than or equal
to the most recent successfully processed TAMP message from that
originator. If the sequence number in a received TAMP message does
not meet these conditions, then the cryptographic module MUST reject
the TAMP message, returning a sequence number failure (seqNumFailure)
error.
Whenever a trust anchor is authorized for TAMP messages, either as a
newly installed trust anchor or as a modification to an existing
trust anchor, if a sequence number value is not provided in the Trust
Anchor Update message, memory MUST be allocated for the sequence
number and set to zero. The first TAMP message received that is
signed by that trust anchor is not rejected based on sequence number
checks, and the sequence number from that first TAMP message is
stored. The TAMP message recipient MUST maintain a database of the
most recent sequence number from a successfully processed TAMP
message from each trust anchor. The index for this database is the
trust anchor public key. This could be the apex trust anchor
operational public key or a management trust anchor public key. In
the first case, the apex trust anchor operational public key is used
Housley, et al. Expires April 9, 2009 [Page 54]
Internet-Draft TAMP October 2008
directly to validate the TAMP message digital signature. In the
second case, a management trust anchor public key is used directly to
validate the TAMP message digital signature.
Sequence number values MUST be 64-bit non-negative integers. Since
ASN.1 encoding of an INTEGER always includes a sign bit, a TAMP
message signer can generate 9,223,372,036,854,775,807 TAMP messages
before exhausting the 64-bit sequence number space, before which the
TAMP message signer MUST transition to a different public/private key
pair. The ability to reset a sequence number provided by the Trust
Anchor Update and Sequence Number Adjust messages is not intended to
avoid the transition to a different key pair; rather, it is intended
to aid recovery from operational errors. A relatively small non-
volatile storage requirement is imposed on the cryptographic module
for the apex trust anchor and each management trust anchor.
When the apex trust anchor or a management trust anchor is replaced
or removed from the cryptographic module, the associated sequence
number storage SHOULD be reclaimed.
Housley, et al. Expires April 9, 2009 [Page 55]
Internet-Draft TAMP October 2008
7. Subordination Processing
The apex trust anchor is unconstrained, which means that
subordination checking is not performed on Trust Anchor Update
messages signed with the apex trust anchor operational public key.
Subordination checking is performed as part of the validation process
of all other Trust Anchor Update messages.
For a Trust Anchor Update message that is not signed with the apex
trust anchor operational public key to be valid, the digital
signature MUST be validated using a management trust anchor
associated with the id-ct-TAMP-update content type, either directly
or via an X.509 certification path originating with the apex trust
anchor operational public key or such a management trust anchor. The
following subordination checks MUST also be performed as part of
validation.
Each Trust Anchor Update message contains one or more individual
updates, each of which is used to add, modify or remove a trust
anchor. For each individual update the constraints of the TAMP
message signer MUST be greater than or equal to the constraints of
the trust anchor in the update. The constraints of the TAMP message
signer and the to-be-updated trust anchor are determined based on the
applicable CMS Content Constraints. Specifically, the constraints of
the TAMP message signer are determined as described in section 3 of
[CCC] passing the special value id-ct-anyContentType and an empty set
of attributes as input; the constraints of the to-be-updated trust
anchor are determined as described below. If the constraints of a
trust anchor in an update exceed the constraints of the signer, that
update MUST be rejected. Each update is considered and accepted or
rejected individually without regard to other updates in the TAMP
message. The constraints of the to-be-updated trust anchors are
determined as follows:
o If the to-be-updated trust anchor is the subject of an add
operation, the constraints are read from the taType.mgmt.taUsage
field of the corresponding TrustAnchorInfo or
CMSContentConstraints of the corresponding Certificate or
TBSCertificate in the update.
o If the to-be-updated trust anchor is the subject of a remove
operation, the trust anchor is located in the message recipient's
trust anchor store using the public key included in the update.
The constraints are read from the taType.mgmt.taUsage (or
equivalent) field in the to-be-updated trust anchor.
o If the to-be-updated trust anchor is the subject of a change
operation, the trust anchor has two distinct sets of constraints
Housley, et al. Expires April 9, 2009 [Page 56]
Internet-Draft TAMP October 2008
that MUST be checked. The trust anchor's pre-change constraints
are determined by locating the trust anchor in the message
recipient's trust anchor store using the public key included in
the update and reading the constraints from the
taType.mgmt.taUsage (or equivalent) field in the trust anchor.
The trust anchor's post-change constraints are read from the
taType.mgmt.taUsage (or equivalent) field of the corresponding
TrustAnchorChangeInfo in the update. If the taType.mgmt.taUsage
(or equivalent) field is not present, then the trust anchor's
post-change constraints are equivalent to the trust anchor's pre-
change constraints.
The following steps can be used to determine if a Trust Anchor Update
message signer is authorized to manage each to-be-updated trust
anchor contained in a Trust Anchor Update message.
o The TAMP message signer's CMS Content Constraints are determined
as described in section 3 of [CCC] passing the special value id-
ct-anyContentType and an empty set of attributes as input. Note,
for implementations that support validation of TAMP messages using
X.509 certificates, it is possible for the TAMP message signer to
have more than one possible certification path that will authorize
it to sign Trust Anchor Update messages, with each certification
path resulting in different CMS Content Constraints. The update
is authorized if the processing below succeeds for any one
certification path of the TAMP message signer. The resulting
subject_constraints variable is used to check each to-be-updated
trust anchor contained in the update message. The message signer
MUST be authorized for the Trust Anchor Update message. This can
be confirmed using the steps described in section 4 of [CCC].
o The constraints of each to-be-updated trust anchor in the TAMP
message MUST be checked against the message signer's constraints
(represented in the message signer's subject_constraints computed
above) using the following steps. For change operations, the
following steps MUST be performed for the trust anchor's pre-
change constraints and the trust anchor's post-change constraints.
* Operations on identity trust anchors are permitted provided the
message signer is authorized for the Trust Anchor Update
message.
* If the to-be-updated trust anchor is unconstrained, the message
signer MUST also be unconstrained, i.e., the message signer's
subject_constraints MUST be set to the special value
anyContentType. If the to-be-updated trust anchor is
unconstrained and the message signer is not, then the message
signer is not authorized to manage the trust anchor and the
Housley, et al. Expires April 9, 2009 [Page 57]
Internet-Draft TAMP October 2008
update MUST be rejected.
* The message signer's authorization for each permitted content
type MUST be checked using the state variables and procedures
similar to those described in sections 3.2 and 3.3 of [CCC].
For each permitted content type in the to-be-updated trust
anchor's constraints,
+ Set cms_effective_attributes equal to the value of the
attrConstraints field from the permitted content type.
+ If the content type does not match an entry in the message
signer's subject_constraints, the message signer is not
authorized to manage the trust anchor and the update MUST be
rejected. Note, the special value id-ct-anyContentType
produces a match for all content types with the resulting
matching entry containing the content type, canSource set to
TRUE and attrConstraints absent.
+ If the content type matches an entry in the message signer's
subject_constraints, the canSource field of the entry is
FALSE and the canSource field in the to-be-updated trust
anchor's privilege is TRUE, the message signer is not
authorized to manage the trust anchor and the update MUST be
rejected.
+ If the content type matches an entry in the message signer's
subject_constraints and the entry's attrConstraints field is
present, then constraints MUST be checked. For each
attrType in the entry's attrConstraints, a corresponding
attribute MUST be present in cms_effective_attributes
containing values from the entry's attrConstraints. If
values appear in the corresponding attribute that are not in
the entry's attrConstraints or if there is no corresponding
attribute, the message signer is not authorized to manage
the trust anchor and the update MUST be rejected.
Once these steps are completed, if the update has not been rejected,
then the message signer is authorized to manage the to-be-updated
trust anchor.
Note that a management trust anchor that has only the id-ct-TAMP-
update permitted content type is useful only for managing identity
trust anchors. It can sign a Trust Anchor Update message, but it
cannot impact a management trust anchor that is associated with any
other content type.
Housley, et al. Expires April 9, 2009 [Page 58]
Internet-Draft TAMP October 2008
8. Implementation Considerations
A public key identifier is used to identify a TAMP message signer.
Since there is no guarantee that the same public key identifier is
not associated with more than one public key, implementations MUST be
prepared for one or more trust anchor to have the same public key
identifier. In practical terms, this means that when a digital
signature validation fails, the implementation MUST see if there is
another trust anchor with the same public key identifier that can be
used to validate the digital signature. While duplicate public key
identifiers are expected to be rare, implementations MUST NOT fail to
find the correct trust anchor when they do occur.
An X.500 distinguished name is used to identify certificate issuers
and certificate subjects. The same X.500 distinguished name can be
associated with more than one trust anchor. However, the trust
anchor public key will be different. The probability that two trust
anchors will have the same X.500 distinguished name and the same
public key identifier but a different public key is diminishingly
small. Therefore, the authority key identifier certificate extension
can be used to resolve X.500 distinguished name collisions.
Housley, et al. Expires April 9, 2009 [Page 59]
Internet-Draft TAMP October 2008
9. Apex trust anchor info certificate extension
Where a Certificate or TBSCertificate structure is used to represent
an Apex trust anchor, contingency key information may be supplied
using the WrappedApexContingencyKey extension. The extension uses
the ApexContingencyKey structure as defined in [TAF], and repeated
below. The fields are used as described in [TAF].
ApexContingencyKey ::= SEQUENCE {
wrapAlgorithm AlgorithmIdentifier,
wrappedContinPubKey OCTET STRING }
The apex trust anchor info certificate extension MAY be critical, and
it MUST appear at most one time in a certificate. The apex trust
anchor info certificate extension is identified by the id-pe-
wrappedApexContinKey object identifier:
id-pe-wrappedApexContinKey OBJECT IDENTIFIER ::=
{ iso(1) identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) pe(1) 20 }
Housley, et al. Expires April 9, 2009 [Page 60]
Internet-Draft TAMP October 2008
10. Security Considerations
The majority of this specification is devoted to the syntax and
semantics of TAMP messages. It relies on other specifications,
especially [TAF], [RFC3852] and [RFC5280], for the syntax and
semantics of CMS protecting content types and X.509 certificates,
respectively. Since TAMP messages that change the trust anchor state
of a cryptographic module are always signed by a Trust Anchor
Manager, no further data integrity or data origin authentication
mechanisms are needed; however, no confidentiality for these messages
is provided. Similarly, certificates are digitally signed, and no
additional data integrity or data origin authentication mechanisms
are needed. Trust anchor configurations, Trust Anchor Manager
certificates, and cryptographic module certificates are not intended
to be sensitive. As a result, this specification does not provide
for confidentiality of TAMP messages.
Security factors outside the scope of this specification greatly
affect the assurance provided. The procedures used by certification
authorities (CAs) to validate the binding of the subject identity to
their public key greatly affect the assurance associated with the
resulting certificate. This is particularly important when issuing
certificates to other CAs. In the context of TAMP, the issuance of
an end entity certificate under a management trust anchor is an act
of delegation. However, such end entities cannot further delegate.
On the other hand, issuance of a CA certificate under a management
trust anchor is an act of delegation where the CA can perform further
delegation. The scope of the delegation can be constrained by
including a CMS content constraints certificate extension [CCC] in a
CA certificate.
X.509 certification path construction involves comparison of X.500
distinguished names. Inconsistent application of name comparison
rules can result in acceptance of invalid X.509 certification paths
or rejection of valid ones. Name comparison can be extremely
complex. To avoid imposing this complexity on cryptographic modules,
any certificate profile used with TAMP SHOULD employ simple name
structures and impose rigorous restrictions on acceptable
distinguished names, including the way that they are encoded. The
goal of that certificate profile should be to enable simple binary
comparison. That is, case conversion, character set conversion,
white space compression, and leading and trailing white space
trimming SHOULD be avoided.
Some digital signature algorithms require the generation of random
one-time values. For example, when generating a DSA digital
signature, the signer MUST generate a random k value [DSS]. Also,
the generation of public/private key pairs relies on random numbers.
Housley, et al. Expires April 9, 2009 [Page 61]
Internet-Draft TAMP October 2008
The use of an inadequate random number generator (RNG) or an
inadequate pseudo-random number generator (PRNG) to generate such
cryptographic values can result in little or no security. An
attacker may find it much easier to reproduce the random number
generation environment, searching the resulting small set of
possibilities, rather than brute force searching the whole space.
Compromise of an identity trust anchor private key permits
unauthorized parties to issue certificates that will be acceptable to
all cryptographic modules configured with the corresponding identity
trust anchor. The unauthorized private key holder will be limited by
the certification path controls associated with the identity trust
anchor. For example, clearance constraints in the identity trust
anchor will determine the clearances that will be accepted in
certificates that are issued by the unauthorized private key holder.
Compromise of a management trust anchor private key permits
unauthorized parties to generate signed messages that will be
acceptable to all cryptographic modules configured with the
corresponding management trust anchor. All devices that include the
compromised management trust anchor can be configured as desired by
the unauthorized private key holder within the limits of the
subordination checks described in Section 7. If the management trust
anchor is associated with content types other than TAMP, then the
unauthorized private key holder can generate signed messages of that
type. For example, if the management trust anchor is associated with
firmware packages, then the unauthorized private key holder can
install different firmware into the cryptographic module.
Compromise of the Apex Trust Anchor operational private key permits
unauthorized parties to generate signed messages that will be
acceptable to all cryptographic modules configured with the
corresponding apex trust anchor. All devices that include that apex
trust anchor can be configured as desired by the unauthorized private
key holder, and the unauthorized private key holder can generate
signed messages of any content type. The optional contingency
private key offers a potential way to recover from such a compromise.
The compromise of a CA's private key leads to the same type of
problems as the compromise of an identity or a management trust
anchor private key. The unauthorized private key holder will be
limited by the certification path controls associated with the trust
anchor. If the CA is subordinate to a management trust anchor, the
scope of potential damage caused by a private key compromise is also
limited by the CMS content constraints certificate extension [CCC] in
the CA certificate, the CMS content constraints on any superior CA
certificates, and the CMS content constraints on the parent
management trust anchor.
Housley, et al. Expires April 9, 2009 [Page 62]
Internet-Draft TAMP October 2008
The compromise of an end entity private key leads to the same type of
problems as the compromise of an identity or a management trust
anchor private key, except that the end entity is unable to issue any
certificates. The unauthorized private key holder will be limited by
the certification path controls associated with the trust anchor. If
the certified public key is subordinate to a management trust anchor,
the scope of potential damage caused by a private key compromise is
also limited by the CMS content constraints certificate extension
[CCC] in the end entity certificate, the CMS content constraints on
any superior CA certificates, and the CMS content constraints on the
parent management trust anchor.
Compromise of a cryptographic module's digital signature private key
permits unauthorized parties to generate signed TAMP response
messages, masquerading as the cryptographic module.
Premature disclosure of the key-encryption key used to encrypt the
apex trust anchor contingency public key may result in early exposure
of the apex trust anchor contingency public key.
To implement TAMP, a cryptographic module needs to be able to parse
messages and certificates. Care must be taken to ensure that there
are no implementation defects in the TAMP message parser or the
processing that acts on the message content. A validation suite is
one way to increase confidence in the parsing of TAMP messages, CMS
content types, signed attributes, and certificates.
Housley, et al. Expires April 9, 2009 [Page 63]
Internet-Draft TAMP October 2008
11. IANA Considerations
There are no IANA considerations. Please delete this section prior
to RFC publication.
Housley, et al. Expires April 9, 2009 [Page 64]
Internet-Draft TAMP October 2008
12. References
12.1. Normative References
[CCC] Housley, R. and C. Wallace, "Cryptographic Message Syntax
(CMS) Content Signature Constraints X.509 Certificate
Extension", in progress.
[PKIXASN1]
Hoffman, P. and J. Schaad, "New ASN.1 Modules for PKIX",
in progress.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2634] Hoffman, P., "Enhanced Security Services for S/MIME",
RFC 2634, June 1999.
[RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO
10646", STD 63, RFC 3629, November 2003.
[RFC3852] Housley, R., "Cryptographic Message Syntax (CMS)",
RFC 3852, July 2004.
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, May 2008.
[TAF] Housley, R., Wallace, C., and S. Ashmore, "Trust Anchor
Format", in progress.
[X.680] "ITU-T Recommendation X.680: Information Technology -
Abstract Syntax Notation One", 1997.
[X.690] "ITU-T Recommendation X.690 Information Technology - ASN.1
encoding rules: Specification of Basic Encoding Rules
(BER), Canonical Encoding Rules (CER) and Distinguished
Encoding Rules (DER)", 1997.
12.2. Informative References
[DSS] "FIPS Pub 186: Digital Signature Standard", May 1994.
[PKCS#6] "PKCS #6: Extended-Certificate Syntax Standard, Version
1.5", November 1993.
[RFC3281] Farrell, S. and R. Housley, "An Internet Attribute
Housley, et al. Expires April 9, 2009 [Page 65]
Internet-Draft TAMP October 2008
Certificate Profile for Authorization", RFC 3281,
April 2002.
[RFC4049] Housley, R., "BinaryTime: An Alternate Format for
Representing Date and Time in ASN.1", RFC 4049,
April 2005.
[RFC4108] Housley, R., "Using Cryptographic Message Syntax (CMS) to
Protect Firmware Packages", RFC 4108, August 2005.
[X.208] "ITU-T Recommendation X.208 - Specification of Abstract
Syntax Notation One (ASN.1)", 1988.
[X.509] "ITU-T Recommendation X.509 - The Directory -
Authentication Framework", 2000.
Housley, et al. Expires April 9, 2009 [Page 66]
Internet-Draft TAMP October 2008
Appendix A. ASN.1 Modules
Appendix A.1 provides the normative ASN.1 definitions for the
structures described in this specification using ASN.1 as defined in
[X.680]. Appendix A.2 provides a module using ASN.1 as defined in
[X.208]. The module in A.2 removes usage of newer ASN.1 features
that provide support for limiting the types of elements that may
appear in certain SEQUENCE and SET constructions. Otherwise, the
modules are compatible in terms of encoded representation, i.e., the
modules are bits-on-the-wire compatible aside from the limitations on
SEQUENCE and SET constituents. A.2 is included as a courtesy to
developers using ASN.1 compilers that do not support current ASN.1.
A.1. ASN.1 Module Using 1993 Syntax
TrustAnchorManagementProtocolVersion2
{ joint-iso-ccitt(2) country(16) us(840) organization(1)
gov(101) dod(2) infosec(1) modules(0) 30 }
DEFINITIONS IMPLICIT TAGS ::=
BEGIN
IMPORTS
TrustAnchorInfo, ApexContingencyKey
FROM TrustAnchorInfo
{ joint-iso-ccitt(2) country(16) us(840) organization(1)
gov(101) dod(2) infosec(1) modules(0) 33 }
ContentType
FROM CryptographicMessageSyntax2004 -- [RFC3852]
{ iso(1) member-body(2) us(840) rsadsi(113549)
pkcs(1) pkcs-9(9) smime(16) modules(0) cms-2004(24) }
AlgorithmIdentifier, Certificate, Name, TBSCertificate
FROM PKIX1Explicit88 -- from [RFC5280]
{ iso(1) identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) id-mod(0)
id-pkix1-explicit(18) }
KeyIdentifier
FROM PKIX1Implicit88 -- from [RFC5280]
{ iso(1) identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) id-mod(0)
id-pkix1-implicit(19) }
EXTENSION, ATTRIBUTE, Attribute
FROM PKIX-CommonTypes -- from [PKIXASN1]
{ iso(1) identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) id-mod(0)
id-mod-pkixCommon(43) } ;
Housley, et al. Expires April 9, 2009 [Page 67]
Internet-Draft TAMP October 2008
TrustAnchorChoice ::= CHOICE {
certificate [0] EXPLICIT Certificate,
tbsCert [1] EXPLICIT TBSCertificate,
taInfo [2] EXPLICIT TrustAnchorInfo }
wrappedApexContinKey EXTENSION ::= {
SYNTAX ApexContingencyKey
IDENTIFIED BY id-pe-wrappedApexContinKey }
id-pe-wrappedApexContinKey OBJECT IDENTIFIER ::=
{ iso(1) identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) pe(1) 20 }
-- Object Identifier Arc for TAMP Message Content Types
id-tamp OBJECT IDENTIFIER ::= {
joint-iso-ccitt(2) country(16) us(840) organization(1)
gov(101) dod(2) infosec(1) formats(2) 77 }
-- CMS Content Types
PKCS7-CONTENT-TYPE ::= TYPE-IDENTIFIER
TAMPContentTypes PKCS7-CONTENT-TYPE ::= {
tamp-status-query |
tamp-status-response |
tamp-update |
tamp-update-confirm |
tamp-apex-update |
tamp-apex-update-confirm |
tamp-community-update |
tamp-community-update-confirm |
tamp-sequence-number-adjust |
tamp-sequence-number-adjust-confirm |
tamp-error,
... -- Expect additional content types --
}
-- TAMP Status Query Message
tamp-status-query PKCS7-CONTENT-TYPE ::=
{ TAMPStatusQuery IDENTIFIED BY id-ct-TAMP-statusQuery }
id-ct-TAMP-statusQuery OBJECT IDENTIFIER ::= { id-tamp 1 }
TAMPStatusQuery ::= SEQUENCE {
version [0] TAMPVersion DEFAULT v2,
Housley, et al. Expires April 9, 2009 [Page 68]
Internet-Draft TAMP October 2008
terse [1] TerseOrVerbose DEFAULT verbose,
query TAMPMsgRef }
TAMPVersion ::= INTEGER { v1(1), v2(2) }
TerseOrVerbose ::= ENUMERATED { terse(1), verbose(2) }
TAMPMsgRef ::= SEQUENCE {
target TargetIdentifier,
seqNum SeqNumber }
TargetIdentifier ::= CHOICE {
hwModules [1] HardwareModuleIdentifierList,
communities [2] CommunityIdentifierList,
allModules [3] NULL }
HardwareModuleIdentifierList ::= SEQUENCE SIZE (1..MAX) OF
HardwareModules
HardwareModules ::= SEQUENCE {
hwType OBJECT IDENTIFIER,
hwSerialEntries SEQUENCE SIZE (1..MAX) OF HardwareSerialEntry }
HardwareSerialEntry ::= CHOICE {
all NULL,
single OCTET STRING,
block SEQUENCE {
low OCTET STRING,
high OCTET STRING } }
CommunityIdentifierList ::= SEQUENCE SIZE (0..MAX) OF Community
Community ::= OBJECT IDENTIFIER
-- TAMP Status Response Message
tamp-status-response PKCS7-CONTENT-TYPE ::=
{ TAMPStatusResponse IDENTIFIED BY id-ct-TAMP-statusResponse }
id-ct-TAMP-statusResponse OBJECT IDENTIFIER ::= { id-tamp 2 }
TAMPStatusResponse ::= SEQUENCE {
version [0] TAMPVersion DEFAULT v2,
query TAMPMsgRef,
response StatusResponse }
StatusResponse ::= CHOICE {
Housley, et al. Expires April 9, 2009 [Page 69]
Internet-Draft TAMP October 2008
terseResponse [0] TerseStatusResponse,
verboseResponse [1] VerboseStatusResponse }
TerseStatusResponse ::= SEQUENCE {
taKeyIds KeyIdentifiers,
communities CommunityIdentifierList OPTIONAL }
KeyIdentifiers ::= SEQUENCE SIZE (1..MAX) OF KeyIdentifier
VerboseStatusResponse ::= SEQUENCE {
taInfo TrustAnchorChoiceList,
continPubKeyDecryptAlg AlgorithmIdentifier OPTIONAL,
communities CommunityIdentifierList OPTIONAL }
TrustAnchorChoiceWithSeqNumber ::= SEQUENCE {
ta TrustAnchorChoice,
seqNumber SeqNumber OPTIONAL
-- seqNumber only present when TA is authorized for TAMP
}
TrustAnchorChoiceList ::= SEQUENCE SIZE (1..MAX) OF
TrustAnchorChoiceWithSeqNumber
-- Trust Anchor Update Message
tamp-update PKCS7-CONTENT-TYPE ::=
{ TAMPUpdate IDENTIFIED BY id-ct-TAMP-update }
id-ct-TAMP-update OBJECT IDENTIFIER ::= { id-tamp 3 }
TAMPUpdate ::= SEQUENCE {
version [0] TAMPVersion DEFAULT v2,
terse [1] TerseOrVerbose DEFAULT verbose,
msgRef TAMPMsgRef,
updates SEQUENCE SIZE (1..MAX) OF TrustAnchorUpdate }
TrustAnchorUpdate ::= CHOICE {
add [1] TrustAnchorChoiceWithSeqNumber,
remove [2] PublicKeyInfo,
change [3] EXPLICIT TrustAnchorChangeInfoChoice }
TrustAnchorChangeInfoChoice ::= CHOICE {
tbsCertChange [0] TBSCertificateChangeInfo,
taChange [1] TrustAnchorChangeInfo }
TBSCertificateChangeInfo ::= SEQUENCE {
serialNumber CertificateSerialNumber OPTIONAL,
Housley, et al. Expires April 9, 2009 [Page 70]
Internet-Draft TAMP October 2008
signature AlgorithmIdentifier OPTIONAL,
issuer Name OPTIONAL,
validity Validity OPTIONAL,
subject Name OPTIONAL,
subjectPublicKeyInfo SubjectPublicKeyInfo,
exts [3] EXPLICIT Extensions OPTIONAL }
TrustAnchorChangeInfo ::= SEQUENCE {
pubKey PublicKeyInfo,
keyId KeyIdentifier OPTIONAL,
taType [0] TrustAnchorChangeType OPTIONAL,
taTitle [1] TrustAnchorTitle OPTIONAL,
certPath [2] CertPathControls OPTIONAL,
exts [3] Extensions OPTIONAL}
TrustAnchorChangeType ::= CHOICE {
mgmt [1] MgmtTrustAnchorInfo,
ident [2] NULL }
-- Trust Anchor Update Confirm Message
tamp-update-confirm PKCS7-CONTENT-TYPE ::=
{ TAMPUpdateConfirm IDENTIFIED BY id-ct-TAMP-updateConfirm }
id-ct-TAMP-updateConfirm OBJECT IDENTIFIER ::= { id-tamp 4 }
TAMPUpdateConfirm ::= SEQUENCE {
version [0] TAMPVersion DEFAULT v2,
update TAMPMsgRef,
confirm UpdateConfirm }
UpdateConfirm ::= CHOICE {
terseConfirm [0] TerseUpdateConfirm,
verboseConfirm [1] VerboseUpdateConfirm }
TerseUpdateConfirm ::= StatusCodeList
StatusCodeList ::= SEQUENCE SIZE (1..MAX) OF StatusCode
VerboseUpdateConfirm ::= SEQUENCE {
status StatusCodeList,
taInfo TrustAnchorChoiceList }
-- Apex Trust Anchor Update Message
tamp-apex-update PKCS7-CONTENT-TYPE ::=
Housley, et al. Expires April 9, 2009 [Page 71]
Internet-Draft TAMP October 2008
{ TAMPApexUpdate IDENTIFIED BY id-ct-TAMP-apexUpdate }
id-ct-TAMP-apexUpdate OBJECT IDENTIFIER ::= { id-tamp 5 }
TAMPApexUpdate ::= SEQUENCE {
version [0] TAMPVersion DEFAULT v2,
terse [1] TerseOrVerbose DEFAULT verbose,
msgRef TAMPMsgRef,
clearTrustAnchors BOOLEAN,
clearCommunities BOOLEAN,
apexTA TrustAnchorChoiceWithSeqNumber }
-- Apex Trust Anchor Update Confirm Message
tamp-apex-update-confirm PKCS7-CONTENT-TYPE ::=
{ TAMPApexUpdateConfirm IDENTIFIED BY
id-ct-TAMP-apexUpdateConfirm }
id-ct-TAMP-apexUpdateConfirm OBJECT IDENTIFIER ::= { id-tamp 6 }
TAMPApexUpdateConfirm ::= SEQUENCE {
version [0] TAMPVersion DEFAULT v2,
apexReplace TAMPMsgRef,
apexConfirm ApexUpdateConfirm }
ApexUpdateConfirm ::= CHOICE {
terseApexConfirm [0] TerseApexUpdateConfirm,
verboseApexConfirm [1] VerboseApexUpdateConfirm }
TerseApexUpdateConfirm ::= StatusCode
VerboseApexUpdateConfirm ::= SEQUENCE {
status StatusCode,
taInfo TrustAnchorChoiceList,
communities CommunityIdentifierList OPTIONAL }
-- Community Update Message
tamp-community-update PKCS7-CONTENT-TYPE ::=
{ TAMPCommunityUpdate IDENTIFIED BY id-ct-TAMP-communityUpdate }
id-ct-TAMP-communityUpdate OBJECT IDENTIFIER ::= { id-tamp 7 }
TAMPCommunityUpdate ::= SEQUENCE {
version [0] TAMPVersion DEFAULT v2,
terse [1] TerseOrVerbose DEFAULT verbose,
Housley, et al. Expires April 9, 2009 [Page 72]
Internet-Draft TAMP October 2008
msgRef TAMPMsgRef,
updates CommunityUpdates }
CommunityUpdates ::= SEQUENCE {
remove [1] CommunityIdentifierList OPTIONAL,
add [2] CommunityIdentifierList OPTIONAL }
-- At least one must be present
-- Community Update Confirm Message
tamp-community-update-confirm PKCS7-CONTENT-TYPE ::=
{ TAMPCommunityUpdateConfirm IDENTIFIED BY
id-ct-TAMP-communityUpdateConfirm }
id-ct-TAMP-communityUpdateConfirm OBJECT IDENTIFIER ::=
{ id-tamp 8 }
TAMPCommunityUpdateConfirm ::= SEQUENCE {
version [0] TAMPVersion DEFAULT v2,
update TAMPMsgRef,
commConfirm CommunityConfirm }
CommunityConfirm ::= CHOICE {
terseCommConfirm [0] TerseCommunityConfirm,
verboseCommConfirm [1] VerboseCommunityConfirm }
TerseCommunityConfirm ::= StatusCode
VerboseCommunityConfirm ::= SEQUENCE {
status StatusCode,
communities CommunityIdentifierList OPTIONAL }
-- Sequence Number Adjust Message
tamp-sequence-number-adjust PKCS7-CONTENT-TYPE ::=
{ SequenceNumberAdjust IDENTIFIED BY id-ct-TAMP-seqNumAdjust }
id-ct-TAMP-seqNumAdjust OBJECT IDENTIFIER ::= { id-tamp 10 }
SequenceNumberAdjust ::= SEQUENCE {
version [0] TAMPVersion DEFAULT v2,
msgRef TAMPMsgRef }
-- Sequence Number Adjust Message
Housley, et al. Expires April 9, 2009 [Page 73]
Internet-Draft TAMP October 2008
tamp-sequence-number-adjust-confirm PKCS7-CONTENT-TYPE ::=
{ SequenceNumberAdjustConfirm IDENTIFIED BY
id-ct-TAMP-seqNumAdjustConfirm }
id-ct-TAMP-seqNumAdjustConfirm OBJECT IDENTIFIER ::= { id-tamp 11 }
SequenceNumberAdjustConfirm ::= SEQUENCE {
version [0] TAMPVersion DEFAULT v2,
adjust TAMPMsgRef,
status StatusCode }
-- TAMP Error Message
tamp-error PKCS7-CONTENT-TYPE ::=
{ TAMPError IDENTIFIED BY id-ct-TAMP-error }
id-ct-TAMP-error OBJECT IDENTIFIER ::= { id-tamp 9 }
TAMPError ::= SEQUENCE {
version [0] TAMPVersion DEFAULT v2,
msgType OBJECT IDENTIFIER,
status StatusCode,
msgRef TAMPMsgRef OPTIONAL }
-- Status Codes
StatusCode ::= ENUMERATED {
success (0),
decodeFailure (1),
badContentInfo (2),
badSignedData (3),
badEncapContent (4),
badCertificate (5),
badSignerInfo (6),
badSignedAttrs (7),
badUnsignedAttrs (8),
missingContent (9),
noTrustAnchor (10),
notAuthorized (11),
badDigestAlgorithm (12),
badSignatureAlgorithm (13),
unsupportedKeySize (14),
unsupportedParameters (15),
signatureFailure (16),
insufficientMemory (17),
unsupportedTAMPMsgType (18),
Housley, et al. Expires April 9, 2009 [Page 74]
Internet-Draft TAMP October 2008
apexTAMPAnchor (19),
improperTAAddition (20),
seqNumFailure (21),
contingencyPublicKeyDecrypt (22),
incorrectTarget (23),
communityUpdateFailed (24),
trustAnchorNotFound (25),
unsupportedTAAlgorithm (26),
unsupportedTAKeySize (27),
unsupportedContinPubKeyDecryptAlg (28),
missingSignature (29),
resourcesBusy (30),
versionNumberMismatch (31),
missingPolicySet (32),
revokedCertificate (33),
unsupportedTrustAnchorFormat (34),
other (127) }
-- Object Identifier Arc for Attributes
id-attributes OBJECT IDENTIFIER ::= { joint-iso-ccitt(2) country(16)
us(840) organization(1) gov(101) dod(2) infosec(1) 5 }
-- TAMP Unsigned Attributes
TAMPUnsignedAttributes ATTRIBUTE ::= {
contingency-public-key-decrypt-key,
... -- Expect additional attributes --
}
-- contingency-public-key-decrypt-key unsigned attribute
contingency-public-key-decrypt-key ATTRIBUTE ::= {
WITH SYNTAX PlaintextSymmetricKey
SINGLE VALUE TRUE
ID id-aa-TAMP-contingencyPublicKeyDecryptKey }
id-aa-TAMP-contingencyPublicKeyDecryptKey OBJECT IDENTIFIER ::= {
id-attributes 63 }
PlaintextSymmetricKey ::= OCTET STRING
END
Housley, et al. Expires April 9, 2009 [Page 75]
Internet-Draft TAMP October 2008
A.2. ASN.1 Module Using 1988 Syntax
TrustAnchorManagementProtocolVersion2_88
{ joint-iso-ccitt(2) country(16) us(840) organization(1)
gov(101) dod(2) infosec(1) modules(0) 31 }
DEFINITIONS IMPLICIT TAGS ::=
BEGIN
IMPORTS
TrustAnchorInfo
FROM TrustAnchorInfo
{ joint-iso-ccitt(2) country(16) us(840) organization(1)
gov(101) dod(2) infosec(1) modules(0) 33 }
ContentType
FROM CryptographicMessageSyntax2004 -- [RFC3852]
{ iso(1) member-body(2) us(840) rsadsi(113549)
pkcs(1) pkcs-9(9) smime(16) modules(0) cms-2004(24) }
AlgorithmIdentifier, Certificate, Name, Attribute, TBSCertificate
FROM PKIX1Explicit88 -- [RFC5280]
{ iso(1) identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) id-mod(0)
id-pkix1-explicit(18) }
KeyIdentifier
FROM PKIX1Implicit88 -- [RFC5280]
{ iso(1) identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) id-mod(0)
id-pkix1-implicit(19) } ;
TrustAnchorChoice ::= CHOICE {
certificate [0] EXPLICIT Certificate,
tbsCert [1] EXPLICIT TBSCertificate,
taInfo [2] EXPLICIT TrustAnchorInfo }
id-pe-wrappedApexContinKey OBJECT IDENTIFIER ::=
{ iso(1) identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) pe(1) 20 }
-- Object Identifier Arc for TAMP Message Content Types
id-tamp OBJECT IDENTIFIER ::= { joint-iso-ccitt(2) country(16) us(840)
organization(1) gov(101) dod(2) infosec(1) formats(2) 77 }
Housley, et al. Expires April 9, 2009 [Page 76]
Internet-Draft TAMP October 2008
-- CMS Content Types
-- TAMP Status Query Message
id-ct-TAMP-statusQuery OBJECT IDENTIFIER ::= { id-tamp 1 }
TAMPStatusQuery ::= SEQUENCE {
version [0] TAMPVersion DEFAULT v2,
terse [1] TerseOrVerbose DEFAULT verbose,
query TAMPMsgRef }
TAMPVersion ::= INTEGER { v1(1), v2(2) }
TerseOrVerbose ::= ENUMERATED { terse(1), verbose(2) }
TAMPMsgRef ::= SEQUENCE {
target TargetIdentifier,
seqNum SeqNumber }
TargetIdentifier ::= CHOICE {
hwModules [1] HardwareModuleIdentifierList,
communities [2] CommunityIdentifierList,
allModules [3] NULL }
HardwareModuleIdentifierList ::= SEQUENCE SIZE (1..MAX) OF
HardwareModules
HardwareModules ::= SEQUENCE {
hwType OBJECT IDENTIFIER,
hwSerialEntries SEQUENCE SIZE (1..MAX) OF HardwareSerialEntry }
HardwareSerialEntry ::= CHOICE {
all NULL,
single OCTET STRING,
block SEQUENCE {
low OCTET STRING,
high OCTET STRING } }
CommunityIdentifierList ::= SEQUENCE SIZE (0..MAX) OF Community
Community ::= OBJECT IDENTIFIER
-- TAMP Status Response Message
id-ct-TAMP-statusResponse OBJECT IDENTIFIER ::= { id-tamp 2 }
TAMPStatusResponse ::= SEQUENCE {
Housley, et al. Expires April 9, 2009 [Page 77]
Internet-Draft TAMP October 2008
version [0] TAMPVersion DEFAULT v2,
query TAMPMsgRef,
response StatusResponse }
StatusResponse ::= CHOICE {
terseResponse [0] TerseStatusResponse,
verboseResponse [1] VerboseStatusResponse }
TerseStatusResponse ::= SEQUENCE {
taKeyIds KeyIdentifiers,
communities CommunityIdentifierList OPTIONAL }
KeyIdentifiers ::= SEQUENCE SIZE (1..MAX) OF KeyIdentifier
VerboseStatusResponse ::= SEQUENCE {
taInfo TrustAnchorChoiceList,
continPubKeyDecryptAlg AlgorithmIdentifier OPTIONAL,
communities CommunityIdentifierList OPTIONAL }
TrustAnchorChoiceWithSeqNumber ::= SEQUENCE {
ta TrustAnchorChoice,
seqNumber SeqNumber OPTIONAL
-- seqNumber only present when TA is authorized for TAMP
}
TrustAnchorChoiceList ::= SEQUENCE SIZE (1..MAX) OF
TrustAnchorChoiceWithSeqNumber
-- Trust Anchor Update Message
id-ct-TAMP-update OBJECT IDENTIFIER ::= { id-tamp 3 }
TAMPUpdate ::= SEQUENCE {
version [0] TAMPVersion DEFAULT v2,
terse [1] TerseOrVerbose DEFAULT verbose,
msgRef TAMPMsgRef,
updates SEQUENCE SIZE (1..MAX) OF TrustAnchorUpdate }
TrustAnchorUpdate ::= CHOICE {
add [1] TrustAnchorChoiceWithSeqNumber,
remove [2] PublicKeyInfo,
change [3] EXPLICIT TrustAnchorChangeInfoChoice }
TrustAnchorChangeInfoChoice ::= CHOICE {
tbsCertChange [0] TBSCertificateChangeInfo,
taChange [1] TrustAnchorChangeInfo }
TBSCertificateChangeInfo ::= SEQUENCE {
Housley, et al. Expires April 9, 2009 [Page 78]
Internet-Draft TAMP October 2008
serialNumber CertificateSerialNumber OPTIONAL,
signature AlgorithmIdentifier OPTIONAL,
issuer Name OPTIONAL,
validity Validity OPTIONAL,
subject Name OPTIONAL,
subjectPublicKeyInfo SubjectPublicKeyInfo,
exts [3] EXPLICIT Extensions OPTIONAL }
TrustAnchorChangeInfo ::= SEQUENCE {
pubKey PublicKeyInfo,
keyId KeyIdentifier OPTIONAL,
taType [0] TrustAnchorChangeType OPTIONAL,
taTitle [1] TrustAnchorTitle OPTIONAL,
certPath [2] CertPathControls OPTIONAL,
exts [3] Extensions OPTIONAL}
TrustAnchorChangeType ::= CHOICE {
mgmt [1] MgmtTrustAnchorInfo,
ident [2] NULL }
-- Trust Anchor Update Confirm Message
id-ct-TAMP-updateConfirm OBJECT IDENTIFIER ::= { id-tamp 4 }
TAMPUpdateConfirm ::= SEQUENCE {
version [0] TAMPVersion DEFAULT v2,
update TAMPMsgRef,
confirm UpdateConfirm }
UpdateConfirm ::= CHOICE {
terseConfirm [0] TerseUpdateConfirm,
verboseConfirm [1] VerboseUpdateConfirm }
TerseUpdateConfirm ::= StatusCodeList
StatusCodeList ::= SEQUENCE SIZE (1..MAX) OF StatusCode
VerboseUpdateConfirm ::= SEQUENCE {
status StatusCodeList,
taInfo TrustAnchorChoiceList }
-- Apex Trust Anchor Update Message
id-ct-TAMP-apexUpdate OBJECT IDENTIFIER ::= { id-tamp 5 }
TAMPApexUpdate ::= SEQUENCE {
Housley, et al. Expires April 9, 2009 [Page 79]
Internet-Draft TAMP October 2008
version [0] TAMPVersion DEFAULT v2,
terse [1] TerseOrVerbose DEFAULT verbose,
msgRef TAMPMsgRef,
clearTrustAnchors BOOLEAN,
clearCommunities BOOLEAN,
apexTA TrustAnchorChoiceWithSeqNumber }
-- Apex Trust Anchor Update Confirm Message
id-ct-TAMP-apexUpdateConfirm OBJECT IDENTIFIER ::= { id-tamp 6 }
TAMPApexUpdateConfirm ::= SEQUENCE {
version [0] TAMPVersion DEFAULT v2,
apexReplace TAMPMsgRef,
apexConfirm ApexUpdateConfirm }
ApexUpdateConfirm ::= CHOICE {
terseApexConfirm [0] TerseApexUpdateConfirm,
verboseApexConfirm [1] VerboseApexUpdateConfirm }
TerseApexUpdateConfirm ::= StatusCode
VerboseApexUpdateConfirm ::= SEQUENCE {
status StatusCode,
taInfo TrustAnchorChoiceList,
communities CommunityIdentifierList OPTIONAL }
-- Community Update Message
id-ct-TAMP-communityUpdate OBJECT IDENTIFIER ::= { id-tamp 7 }
TAMPCommunityUpdate ::= SEQUENCE {
version [0] TAMPVersion DEFAULT v2,
terse [1] TerseOrVerbose DEFAULT verbose,
msgRef TAMPMsgRef,
updates CommunityUpdates }
CommunityUpdates ::= SEQUENCE {
remove [1] CommunityIdentifierList OPTIONAL,
add [2] CommunityIdentifierList OPTIONAL }
-- At least one must be present
-- Community Update Confirm Message
id-ct-TAMP-communityUpdateConfirm OBJECT IDENTIFIER ::= { id-tamp 8 }
Housley, et al. Expires April 9, 2009 [Page 80]
Internet-Draft TAMP October 2008
TAMPCommunityUpdateConfirm ::= SEQUENCE {
version [0] TAMPVersion DEFAULT v2,
update TAMPMsgRef,
commConfirm CommunityConfirm }
CommunityConfirm ::= CHOICE {
terseCommConfirm [0] TerseCommunityConfirm,
verboseCommConfirm [1] VerboseCommunityConfirm }
TerseCommunityConfirm ::= StatusCode
VerboseCommunityConfirm ::= SEQUENCE {
status StatusCode,
communities CommunityIdentifierList OPTIONAL }
-- Sequence Number Adjust Message
id-ct-TAMP-seqNumAdjust OBJECT IDENTIFIER ::= { id-tamp 10 }
SequenceNumberAdjust ::= SEQUENCE {
version [0] TAMPVersion DEFAULT v2,
msgRef TAMPMsgRef }
-- Sequence Number Adjust Message
id-ct-TAMP-seqNumAdjustConfirm OBJECT IDENTIFIER ::= { id-tamp 11 }
SequenceNumberAdjustConfirm ::= SEQUENCE {
version [0] TAMPVersion DEFAULT v2,
adjust TAMPMsgRef,
status StatusCode }
-- TAMP Error Message
id-ct-TAMP-error OBJECT IDENTIFIER ::= { id-tamp 9 }
TAMPError ::= SEQUENCE {
version [0] TAMPVersion DEFAULT v2,
msgType OBJECT IDENTIFIER,
status StatusCode,
msgRef TAMPMsgRef OPTIONAL }
-- Status Codes
Housley, et al. Expires April 9, 2009 [Page 81]
Internet-Draft TAMP October 2008
StatusCode ::= ENUMERATED {
success (0),
decodeFailure (1),
badContentInfo (2),
badSignedData (3),
badEncapContent (4),
badCertificate (5),
badSignerInfo (6),
badSignedAttrs (7),
badUnsignedAttrs (8),
missingContent (9),
noTrustAnchor (10),
notAuthorized (11),
badDigestAlgorithm (12),
badSignatureAlgorithm (13),
unsupportedKeySize (14),
unsupportedParameters (15),
signatureFailure (16),
insufficientMemory (17),
unsupportedTAMPMsgType (18),
apexTAMPAnchor (19),
improperTAAddition (20),
seqNumFailure (21),
contingencyPublicKeyDecrypt (22),
incorrectTarget (23),
communityUpdateFailed (24),
trustAnchorNotFound (25),
unsupportedTAAlgorithm (26),
unsupportedTAKeySize (27),
unsupportedContinPubKeyDecryptAlg (28),
missingSignature (29),
resourcesBusy (30),
versionNumberMismatch (31),
missingPolicySet (32),
revokedCertificate (33),
unsupportedTrustAnchorFormat (34),
other (127) }
-- Object Identifier Arc for Attributes
id-attributes OBJECT IDENTIFIER ::= { joint-iso-ccitt(2) country(16)
us(840) organization(1) gov(101) dod(2) infosec(1) 5 }
-- id-aa-TAMP-contingencyPublicKeyDecryptKey uses
-- PlaintextSymmetricKey syntax
id-aa-TAMP-contingencyPublicKeyDecryptKey OBJECT IDENTIFIER ::= {
id-attributes 63 }
Housley, et al. Expires April 9, 2009 [Page 82]
Internet-Draft TAMP October 2008
PlaintextSymmetricKey ::= OCTET STRING
END
Housley, et al. Expires April 9, 2009 [Page 83]
Internet-Draft TAMP October 2008
Authors' Addresses
Russ Housley
Vigil Security, LLC
918 Spring Knoll Drive
Herndon, VA 20170
Email: housley@vigilsec.com
Sam Ashmore
National Security Agency
Suite 6751
9800 Savage Road
Fort Meade, MD 20755
Email: srashmo@radium.ncsc.mil
Carl Wallace
Cygnacom Solutions
Suite 5200
7925 Jones Branch Drive
McLean, VA 22102
Email: cwallace@cygnacom.com
Housley, et al. Expires April 9, 2009 [Page 84]
Internet-Draft TAMP October 2008
Full Copyright Statement
Copyright (C) The IETF Trust (2008).
This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Intellectual Property
The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at
ietf-ipr@ietf.org.
Housley, et al. Expires April 9, 2009 [Page 85]