KEYPROV Working Group Sean Turner, IECA
Internet Draft Russ Housley, Vigil Security
Intended Status: Standard Track October 20, 2009
Expires: April 20, 2010
Symmetric Key Package Content Type
draft-ietf-keyprov-symmetrickeyformat-06.txt
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Abstract
This document defines the symmetric key format content type. It is
transport independent. The Cryptographic Message Syntax can be used
to digitally sign, digest, authenticate, or encrypt this content
type.
Table of Contents
1. Introduction...................................................3
1.1. Requirements Terminology..................................3
1.2. ASN.1 Syntax Notation.....................................3
2. Symmetric Key Package Content Type.............................3
3. PSKC Attributes................................................4
3.1. PSKC Key Package Attributes...............................5
3.1.1. Device Information Attributes........................5
3.1.2. Cryptographic Module Information Attributes..........7
3.2. PSKC Key Attributes.......................................7
3.2.1. Key Identifier.......................................7
3.2.2. Algorithm............................................8
3.2.3. Issuer...............................................8
3.2.4. Key Profile Identifier...............................8
3.2.5. Friendly Name........................................8
3.2.6. Algorithm Parameters.................................9
3.2.7. Counter.............................................11
3.2.8. Time................................................11
3.2.9. Time Interval.......................................11
3.2.10. Time Drift.........................................11
3.2.11. Value MAC..........................................12
3.3. Key Policy Attributes....................................12
3.3.1. Start Date..........................................12
3.3.2. Expiry Date.........................................12
3.3.3. Number of Transactions..............................13
3.3.4. Key Usage...........................................13
3.3.5. PIN Policy..........................................14
4. Key Encoding..................................................15
4.1. AES Key Encoding.........................................16
4.2. Triple DES Key Encoding..................................16
5. Security Considerations.......................................17
6. IANA Considerations...........................................17
7. References....................................................17
7.1. Normative References.....................................17
7.2. Non-Normative References.................................18
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APPENDIX A: ASN.1 Modules........................................18
1. Introduction
This document defines the symmetric key format content type. It is
transport independent. The Cryptographic Message Syntax (CMS)
[RFC5652] can be used to digitally sign, digest, authenticate, or
encrypt this content type.
The uses cases that motivated this work are elaborated in [PSKC].
They are omitted to avoid duplication.
This document also includes Abstract Syntax Notation One (ASN.1)
definitions of the Extensile Markup Language (XML) element and
attributes defined in [PSKC].
1.1. Requirements 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 [RFC2119].
1.2. ASN.1 Syntax Notation
The key package is defined using the ASN.1 [X.680, X.681, X.682, and
X.683].
2. Symmetric Key Package Content Type
The symmetric key package content type is used to transfer one or
more plaintext symmetric keys from one party to another. A symmetric
key package MAY be encapsulated in one or more CMS protecting content
types. This content type must be Distinguished Encoding Rules (DER)
encoded [X.690].
The symmetric key package content type has the following syntax:
PKCS7-CONTENT-TYPE ::= TYPE-IDENTIFIER
symmetric-key-package PKCS7-CONTENT-TYPE ::=
{ SymmetricKeyPackage IDENTIFIED BY id-ct-KP-sKeyPackage }
id-ct-KP-sKeyPackage OBJECT IDENTIFIER ::=
{ iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
smime(16) ct(1) 25 }
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SymmetricKeyPackage ::= SEQUENCE {
version KeyPkgVersion DEFAULT v1,
sKeyPkgAttrs [0] SEQUENCE SIZE (1..MAX) OF Attribute OPTIONAL,
sKeys SymmetricKeys }
SymmetricKeys ::= SEQUENCE SIZE (1..MAX) OF OneSymmetricKey
OneSymmetricKey ::= SEQUENCE {
sKeyAttrs SEQUENCE SIZE (1..MAX) OF Attribute OPTIONAL,
sKey OCTET STRING OPTIONAL }
-- At least sKeyAttrs or sKey MUST be present.
KeyPkgVersion ::= INTEGER { v1(1), ... }
The SymmetricKeyPackage fields are used as follows:
- version identifies version of the symmetric key package content
structure. For this version of the specification, the default
value, v1, MUST be used.
- sKeyPkgAttrs optionally provides attributes that apply to all of
the symmetric keys in the package. If an attribute appears here it
MUST NOT also be included in sKeyAttrs.
- sKeys contains a sequence of OneSymmetricKey values. This
structure is discussed below.
The OneSymmetricKey fields are used as follows:
- sKeyAttrs optionally provides attributes that apply to one
symmetric key. If an attribute appears here it MUST NOT also be
included in sKeyPkgAttrs.
- sKey optionally contains the key value encoded as an OCTET STRING.
The OneSymmetricKey field MUST include either sKeyAttrs, or sKey, or
sKeyAttrs and sKey.
3. PSKC Attributes
The following attributes are defined to assist those using the
symmetric key package defined in this document as part of a Portable
Symmetric Key Container protocol [PSKC]. [PSKC] should be consulted
for the definitive attribute descriptions. The attributes fall in to
three categories. The first category includes attributes that apply
to a key package, and these attributes will generally appear in
sKeyPkgAttrs. The second category includes attributes that apply to
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a particular key, and these attributes will generally appear in
sKeyAttrs. The third category includes attributes that apply to a key
policy. Of the attributes defined next, only the Key Identifier
(Section 3.2.1) and Algorithm (Section 3.2.2) key attributes MUST be
included. All other attributes are OPTIONAL.
Like PSKC, the Symmetric Key Content Type supports extensibility.
Primarily this is accomplished through the definition and inclusion
of new attributes, but in some instances where the attribute contains
more than one type the ASN.1 "..." extensibility mechanism is
employed.
A straightforward approach to conversion from XML types to ASN.1 is
employed. The <xs:string> type converts to UTF8String; the XML
<xs:dateTime> type converts to GeneralizedTime; and the XML integer
types convert to INTEGER or BinaryTime [RFC4049].
3.1. PSKC Key Package Attributes
PSKC key package attributes apply to an entire key package. These
attributes can be categorized by two different attribute collections:
device information and cryptographic module attributes. All of these
key package attributes are OPTIONAL.
3.1.1. Device Information Attributes
Device Information attributes when taken together uniquely identify a
device to which the Symmetric Key Package is provisioned.
3.1.1.1. Manufacturer
The Manufacturer attribute indicates the manufacturer of the device.
The attribute definition is as follows:
at-pskc-manufacturer ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-manufacturer }
id-pskc-manufacturer OBJECT IDENTIFIER ::= { TBD }
3.1.1.2. Serial Number
The Serial Number attribute indicates the serial number of the
device. The attribute definition is as follows:
at-pskc-serialNo ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-serialNo }
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id-pskc-serialNo OBJECT IDENTIFIER ::= { TBD }
3.1.1.3. Model
The Model attribute indicates the model of the device. The attribute
definition is as follows:
at-pskc-model ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-model }
id-pskc-model OBJECT IDENTIFIER ::= { TBD }
3.1.1.4. Issue Number
The Issue Number attribute contains an issue number to distinguish
between two devices with the same serial number. The attribute
definition is as follows:
at-pskc-issueNo ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-issueNo }
id-pskc-issueNo OBJECT IDENTIFIER ::= { TBD }
3.1.1.5. Device Binding
The Device Binding attribute provides an opaque identifier that
allows keys to be bound to the device or to a class of devices.
When loading keys into a device, the attribute's value MUST be
checked against information provided to the user via out-of-band
mechanisms. The implementation then ensures that the correct device
or class of device is being used with respect to the provisioned key.
at-pskc-deviceBinding ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-deviceBinding }
id-pskc-deviceBinding OBJECT IDENTIFIER ::= { TBD }
3.1.1.6. Start Date
When included in sKeyPkgAttrs, the Start Date attribute indicates the
start date for a device. The date MUST be expressed in UTC form with
no time zone component. Implementations SHOULD NOT rely on time
resolution finer than milliseconds and MUST NOT generate time
instants that specify leap seconds. The attribute definition is as
follows:
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at-pskc-startDate ATTRIBUTE ::= {
TYPE GeneralizedTime IDENTIFIED BY id-pskc-startDate }
id-pskc-startDate OBJECT IDENTIFIER ::= { TBD }
3.1.1.7. Expiry Date
When included in sKeyPkgAttrs, the Expiry Date attribute indicates
the expiry date for a device. The date MUST be expressed in UTC form
with no time zone component. Implementations SHOULD NOT rely on time
resolution finer than milliseconds and MUST NOT generate time
instants that specify leap seconds. The attribute definition is as
follows:
at-pskc-expiryDate ATTRIBUTE ::= {
TYPE GeneralizedTime IDENTIFIED BY id-pskc-expiryDate }
id-pskc-expiryDate OBJECT IDENTIFIER ::= { TBD }
3.1.2. Cryptographic Module Information Attributes
Cryptographic Module attributes uniquely identify a cryptographic
module. This is useful when the device contains more than one
cryptographic module. At this time only one attribute is defined.
3.1.2.1. Cryptographic Module Identifier
When included in sKeyPkgAttrs, the Identifier attribute uniquely
identifies the cryptographic module to which the key is being or was
provisioned. The attribute definition is as follows:
at-pskc-id ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-id }
id-pskc-id OBJECT IDENTIFIER ::= { TBD }
3.2. PSKC Key Attributes
PSKC key attributes apply to a specific key. As noted earlier, the
Key Identifier (Sec 3.2.1) and Algorithm (Sec 3.2.2) key attributes
are REQUIRED. All other attributes are OPTIONAL.
3.2.1. Key Identifier
When included in sKeyAttrs, the Identifier attribute uniquely
identifies the key. The syntax is found in Section 3.1.2.1.
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3.2.2. Algorithm
The Algorithm attribute uniquely identifies the PSKC algorithm
profile. Values may be taken from [PSKC-ALGORITHM-PROFILES]. The
attribute definition is as follows:
at-pskc-algorithm ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-algorithm }
id-pskc-algorithm OBJECT IDENTIFIER ::= { TBD }
3.2.3. Issuer
The Issuer attribute names the entity that issued the key. The
attribute definition is as follows:
at-pskc-issuer ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-issuer }
id-pskc-issuer OBJECT IDENTIFIER ::= { TBD }
3.2.4. Key Profile Identifier
The Key Profile Identifier attribute carries a unique identifier used
between the sending and receiving parties to establish a set of key
attribute values that are not transmitted within the container but
agreed between the two parties out of band. This attribute will then
represent the unique reference to a set of key attribute values.
at-pskc-keyProfileId ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-keyProfileId }
id-pskc-keyProfileId OBJECT IDENTIFIER ::= { TBD }
3.2.5. Friendly Name
The Friendly Name attribute contains a human readable name for the
secret key. The attribute definition is as follows:
at-pskc-friendlyName ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-friendlyName }
id-pskc-friendlyName OBJECT IDENTIFIER ::= { TBD }
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3.2.6. Algorithm Parameters
The Algorithm Parameters attribute contains parameters that influence
the result of the algorithmic computation, for example response
truncation and format in One-Time Password (OTP) and Challenge-
Response (CR) algorithms.
at-pskc-algorithmParameters ATTRIBUTE ::= {
TYPE PSKCAlgorithmParameters
IDENTIFIED BY id-pskc-algorithmParameters }
id-pskc-algorithmParameters OBJECT IDENTIFIER ::= { TBD }
The Algorithm Parameters attribute has the following syntax:
PSKCAlgorithmParameters ::= CHOICE {
challengeFormat [0] ChallengeFormat,
responseFormat [1] ResponseFormat,
... }
ChallengeFormat ::= SEQUENCE {
encoding Encoding,
checkDigit BOOLEAN OPTIONAL,
min INTEGER,
max INTEGER,
... }
Encoding ::= CHOICE {
decimal [0] UTF8String ("DECIMAL"),
hexidecimal [1] UTF8String ("HEXIDECIMAL"),
alphanumeric [2] UTF8String ("ALPHANUMERIC"),
base64 [3] UTF8String ("BASE64"),
binary [4] UTF8String ("BINARY") }
ResponseFormat ::= SEQUENCE {
encoding Encoding,
length INTEGER,
checkDigit BOOLEAN OPTIONAL,
... }
The fields in PSKCAlgorithmParameters have the following meanings:
o ChallengeFormat defines the characteristics of the challenge in a
CR usage scenario whereby the following fields are defined:
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o encoding specifies the encoding of the challenge accepted by
the device and MUST be one of the following values: DECIMAL,
HEXIDECIMAL, ALPHANUMERIC, BASE64, or BINARY.
o checkDigit indicates whether a device needs to check the
appended Luhn check digit, as defined in [LUHN], contained in a
challenge. The checkDigit MUST NOT be present if the encoding
value is anything other than 'DECIMAL'. A value of TRUE
indicates that the device will check the appended Luhn check
digit in a provided challenge. A value of FALSE indicates that
the device will not check the appended Luhn check digit in the
challenge.
o min defines the minimum size of the challenge accepted by the
device for CR mode. If encoding is 'DECIMAL', 'HEXADECIMAL' or
'ALPHANUMERIC' this value indicates the minimum number of
digits/characters. If encoding is 'BASE64' or 'BINARY', this
value indicates the minimum number of bytes of the unencoded
value.
o max defines the maximum size of the challenge accepted by the
device for CR mode. If encoding is 'DECIMAL', 'HEXADECIMAL' or
'ALPHANUMERIC' this value indicates the maximum number of
digits/characters. If the encoding is 'BASE64' or 'BINARY',
this value indicates the maximum number of bytes of the
unencoded value.
o ResponseFormat defines the characteristics of the result of a
computation and defines the format of the OTP or the response to
a challenge. For cases where the key is a personal
identification number (PIN) value, this element contains the
format of the PIN itself (e.g., DECIMAL, length 4 for a 4 digit
PIN). The following fields are defined:
o encoding specifies the encoding of the response generated by
the device and MUST be one of the following values: DECIMAL,
HEXADECIMAL, ALPHANUMERIC, BASE64, or BINARY.
o length defines the length of the response generated by the
device. If encoding is 'DECIMAL', 'HEXADECIMAL' or
'ALPHANUMERIC' this value indicates the number of
digits/characters. If encoding is 'BASE64' or 'BINARY', this
value indicates the number of bytes of the unencoded value.
o checkDigit indicates whether the device needs to append a Luhn
check digit, as defined in [LUHN], to the response. This is
only valid if encoding attribute is 'DECIMAL'. If the value is
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TRUE then the device will append a Luhn check digit to the
response. If the value is FALSE, then the device will not
append a Luhn check digit to the response.
3.2.7. Counter
The Counter attribute contains the event counter for event-based OTP
algorithms. The attribute definition is as follows:
at-pskc-counter ATTRIBUTE ::= {
TYPE INTEGER IDENTIFIED BY id-pskc-counter }
id-pskc-counter OBJECT IDENTIFIER ::= { TBD }
3.2.8. Time
The Time attribute conveys the time for time-based OTP algorithms.
If the Time Interval attribute is included, then this element carries
the number of time intervals passed for a specific start point. It
uses the BinaryTime syntax from [RFC4049]. The attribute definition
is as follows:
at-pskc-time ATTRIBUTE ::= {
TYPE BinaryTime IDENTIFIED BY id-pskc-time }
id-pskc-time OBJECT IDENTIFIER ::= { TBD }
3.2.9. Time Interval
The Time Interval attribute conveys the time interval value for time-
based OTP algorithms. It uses the BinaryTime syntax from [RFC4049].
The attribute definition is as follows:
at-pskc-timeInterval ATTRIBUTE ::= {
TYPE BinaryTime IDENTIFIED BY id-pskc-time }
id-pskc-timeInterval OBJECT IDENTIFIER ::= { TBD }
3.2.10. Time Drift
The Time Drift attribute contains the device clock drift value, the
number of seconds per day the device clocks drifts, for time-based
OTP algorithms. It uses the BinaryTime syntax from [RFC4049]. The
attribute definition is as follows:
at-pskc-timeDrift ATTRIBUTE ::= {
TYPE BinaryTime IDENTIFIED BY id-pskc-time }
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id-pskc-timeDrift OBJECT IDENTIFIER ::= { TBD }
3.2.11. Value MAC
The Value MAC attribute is a Message Authentication Code (MAC)
generated from the encrypted value in case the encryption algorithm
does not support integrity checks (e.g., AES-CBC does not provide
integrity while AES Key Wrap with MLI does). The attribute definition
is as follows:
at-pskc-valueMAC ATTRIBUTE ::= {
TYPE ValueMac IDENTIFIED BY id-pskc-valueMAC }
id-pskc-valueMAC OBJECT IDENTIFIER ::= { TBD }
ValueMac ::= SEQUENCE {
macAlgorithm UTF8String,
mac UTF8String }
The fields in ValueMac have the following meanings:
o macAlgorithm identifies the MAC algorithm used to generate the
value placed in digest. Values may be taken from [PSKC-ALGORITHM-
PROFILES].
o mac is the mac value.
3.3. Key Policy Attributes
Key policy attributes indicate a policy that can be attached to a
key. These attributes are defined in the subsections that follow.
3.3.1. Start Date
When included in sKeyPkgAttrs, the Start Date attribute indicates the
start of the keys validity. The date MUST be expressed in UTC form
with no time zone component. Implementations SHOULD NOT rely on time
resolution finer than milliseconds and MUST NOT generate time
instants that specify leap seconds. The attribute definition is as
in Section 3.1.1.6.
3.3.2. Expiry Date
When included in sKeyAttrs, the Expiry Date attribute indicates the
end of the key's validity period. The date MUST be expressed in UTC
form with no time zone component. Implementations SHOULD NOT rely on
time resolution finer than milliseconds and MUST NOT generate time
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instants that specify leap seconds. The attribute definition is as in
Section 3.1.1.7.
3.3.3. Number of Transactions
The Number of Transactions attribute indicates the maximum number of
times a key carried within the package can be used. When this
element is omitted there is no restriction regarding the number of
times a key can be used. The attribute definition is as follows:
at-pskc-numberOfTransactions ATTRIBUTE ::= {
TYPE INTEGER IDENTIFIED BY id-pskc-numberOfTransactions }
id-pskc-numberOfTransactions OBJECT IDENTIFIER ::= { TBD }
3.3.4. Key Usage
The Key Usage attribute constrains the intended usage of the key.
The recipient MUST enforce the key usage. The attribute definition
is as follows:
at-pskc-keyUsage ATTRIBUTE ::= {
TYPE PSKCKeyUsages IDENTIFIED BY id-pskc-keyUsages }
id-pskc-keyUsages OBJECT IDENTIFIER ::= { TBD }
PSKCKeyUsages ::= SEQUENCE OF PSKCKeyUsage
PSKCKeyUsage ::= CHOICE {
otp [0] UTF8String ("OTP"),
cr [1] UTF8String ("CR"),
encrypt [2] UTF8String ("Encrypt"),
integrity [3] UTF8String ("Integrity"),
verify [4] UTF8String ("Verify"),
unlock [5] UTF8String ("Unlock"),
decrypt [6] UTF8String ("Decrypt"),
keyWrap [7] UTF8String ("KeyWrap"),
unwrap [8] UTF8String ("Unwrap"),
derive [9] UTF8String ("Derive"),
generate [10] UTF8String ("Generate") }
The fields in PSKCKeyUsage have the following meanings:
o OTP: The key MUST only be used for OTP generation.
o CR: The key MUST only be used for Challenge/Response purposes.
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o Encrypt: The key MUST only be used for data encryption purposes.
o Integrity: The key MUST only be used to generate a keyed message
digest for data integrity or authentication purposes.
o Verify: The key MUST only be used to verify a keyed message
digest for data integrity or authentication purposes. (is converse
of Integrity)
o Unlock: The key MUST only be used for an inverse challenge
response in the case where a user has locked the device by
entering a wrong PIN too many times (for devices with PIN-input
capability).
o Decrypt: The key MUST only be used for data decryption purposes.
o KeyWrap: The key MUST only be used for key wrap purposes.
o Unwrap: The key MUST only be used for key unwrap purposes.
o Derive: The key MUST only be used with a key derivation function
to derive a new key (see also Section 8.2.4 of [NIST800-57]).
o Generate: The key MUST only be used to generate a new key based
on a random number and the previous value of the key (see also
Section 8.1.5.2.1 of [NIST800-57]).
3.3.5. PIN Policy
The PIN Policy attribute allows policy about the PIN usage to be
associated with the key. The attribute definition is as follows:
at-pskc-pinPolicy ATTRIBUTE ::= {
TYPE PINPolicy IDENTIFIED BY id-pskc-pinPolicy }
id-pskc-pinPolicy OBJECT IDENTIFIER ::= { TBD }
PINPolicy ::= SEQUENCE {
pinKeyId [0] UTF8String OPTIONAL,
pinUsageMode [1] PINUsageMode,
maxFailedAttempts [2] INTEGER OPTIONAL,
minLength [3] INTEGER OPTIONAL,
maxLength [4] INTEGER OPTIONAL,
pinEncoding [4] Encoding OPTIONAL }
PINUsageMode ::= CHOICE {
local [0] UTF8String ("Local"),
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prepend [1] UTF8String ("Prepend"),
append [2] UTF8String ("Append"),
algorithmic [3] UTF8String ("Algorithmic") }
The fields in PIN Policy have the following meanings:
o pinKeyId uniquely identifies the key held within this container
that contains the value of the PIN that protects the key.
o pinUsageMode indicates the way the PIN is used during the usage of
the key. The following values are defined: Local, Prepend,
Append, Algorithmic.
o maxFailedAttempts indicates the maximum number of times the PIN
may be entered wrongly before it MUST NOT be possible to use the
key anymore.
o minLength indicates the minimum length of a PIN that can be set to
protect the associated key. It MUST NOT be possible to set a PIN
shorter than this value. If pinEncoding is 'DECIMAL',
'HEXADECIMAL' or 'ALPHANUMERIC' this value indicates the number of
digits/ characters. If pinEncoding is 'BASE64' or 'BINARY', this
value indicates the number of bytes of the unencoded value.
o maxLength indicates the maximum length of a PIN that can be set to
protect this key. It MUST NOT be possible to set a PIN longer
than this value. If pinEncoding is 'DECIMAL', 'HEXADECIMAL' or
'ALPHANUMERIC' this value indicates the number of
digits/characters. If the pinEncoding is 'BASE64' or 'BINARY',
this value indicates the number of bytes of the unencoded value.
o pinEncoding is based on Encoding, which is defined in Section
3.2.6, and specifies encoding of the PIN and MUST be one of the
following values: DECIMAL, HEXADECIMAL, ALPHANUMERIC, BASE64, or
BINARY.
If pinUsageMode is set to "Local" then the device MUST enforce the
restriction indicated in maxFailedAttempts, minLength, maxLength and
pinEncoding, otherwise it MUST be enforced on the server side.
4. Key Encoding
Two parties receiving the same key as an sKey OCTET STRING must make
use of the key in exactly the same way in order to interoperate. To
ensure that, it is necessary to define a correspondence between the
abstract syntax of sKey and the notation in the standard algorithm
description that defines how the key is used. The next sections
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establish that correspondence for the algorithms AES [FIPS197] and
TDEA [SP800-67].
4.1. AES Key Encoding
[FIPS197] section 5.2, titled Key Expansion, uses the input key as an
array of bytes indexed starting at 0. The first octet of sKey SHALL
become the key byte in AES labeled index 0 in [FIPS197] SHALL be the
first octet of sKey, and the other key bytes SHALL follow in index
order.
Proper parsing and key load of the contents of sKey for AES SHALL be
determined by using the following sKey octet string to generate and
match the key expansion test vectors in [FIPS197] Appendix A for AES
Cipher Key: 2b 7e 15 16 28 ae d2 a6 ab f7 15 88 09 cf 4f 3c
Tag Length Value
04 16 2b 7e 15 16 28 ae d2 a6 ab f7 15 88 09 cf 4f 3c
4.2. Triple DES Key Encoding
A Triple-DES key consists of three keys for the cryptographic engine
(Key1, Key2, and Key3) that are each 64 bits (even though only 56 are
used); the three keys are also referred to as a key bundle (KEY)
[SP800-67]. A key bundle may employ either two or three mutually
independent keys. When only two are employed (called two-key Triple
DES), then Key1 = Key3.
Each key in a Triple-DES key bundle is expanded into a key schedule
according to a procedure defined in [SP800-67] Appendix A. That
procedure numbers the bits in the key from 1 to 64, with number 1
being the left-most, or most significant bit. The first octet of
sKey SHALL be bits 1 through 8 of Key1 with bit 1 being the msb. The
second octet of sKey SHALL be bits 9 through 16 of Key1, and so
forth, so that the trailing octet of sKEY SHALL be bits 57 through 64
of Key3 (or Key2 for two-key Triple DES).
Proper parsing and key load of the contents of sKey for Triple-DES
SHALL be determined by using the following sKey octet string to
generate and match the key expansion test vectors in [SP800-67]
appendix B for the key bundle:
Key1 = 0123456789ABCDEF
Key2 = 23456789ABCDEF01
Key3 = 456789ABCDEF0123
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Tag Length Value
04 24 0123456789ABCDEF 23456789ABCDEF01 456789ABCDEF0123
5. Security Considerations
The symmetric key package contents are not protected. This content
type can be combined with a security protocol to protect the contents
of the package.
6. IANA Considerations
None: All identifiers are already registered. Please remove this
section prior to publication as an RFC.
7. References
7.1. Normative References
[FIPS197] National Institute of Standards. "FIPS Pub 197: Advanced
Encryption Standard (AES)", 26 November 2001.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4049] Housley, R., "BinaryTime: An Alternate Format for
Representing Date and Time in ASN.1", RFC 4049, April 2005.
[X.680] ITU-T Recommendation X.680 (2002) | ISO/IEC 8824-1:2002.
Information Technology - Abstract Syntax Notation One.
[X.681] ITU-T Recommendation X.681 (2002) | ISO/IEC 8824-2:2002.
Information Technology - Abstract Syntax Notation One: Information
Object Specification.
[X.682] ITU-T Recommendation X.682 (2002) | ISO/IEC 8824-3:2002.
Information Technology - Abstract Syntax Notation One: Constraint
Specification.
[X.683] ITU-T Recommendation X.683 (2002) | ISO/IEC 8824-4:2002.
Information Technology - Abstract Syntax Notation One:
Parameterization of ASN.1 Specifications.
[X.690] ITU-T Recommendation X.690 (2002) | ISO/IEC 8825-1:2002.
Information Technology - ASN.1 encoding rules: Specification of Basic
Encoding Rules (BER), Canonical Encoding Rules (CER) and
Distinguished Encoding Rules (DER).
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[SP800-67] National Institute of Standards and Technology, "NIST
Special Publication 800-67 Version 1.1: Recommendation for the Triple
Data Encryption Algorithm (TDEA) Block Cipher", NIST Special
Publication 800-67, May 2008.
7.2. Non-Normative References
[LUHN] Luhn, H., "Luhn algorithm", US Patent 2950048, August 1960,
http://patft.uspto.gov/netacgi/nph-Parser?patentnumber=2950048.
[PSKC] Hoyer, P., Pei, M., and S. Machani, "Portable Symmetric Key
Container (PSKC), draft-ietf-keyprov-pskc-03.txt, work-in-progress.
//** RFC EDITOR: Please replace [PSKC] with [RFCXXXX] where XXXX is
the draft-ietf-keyprov-pskc's RFC #. Make the replacements here and
elsewhere in the document. **//
[PSKC-ALGORITHM-PROFILES] Hoyer, P., Pei, M., Machani, S., and A.
Doherty, "Additional Portable Symmetric Key Container (PSKC)
Algorithm Profiles", Internet Draft Informational, URL:
http://tools.ietf.org/html/draft-hoyer-keyprov-pskc-algorithm-
profiles-00, December 2008.
//** RFC EDITOR: Please replace [PSKC-ALGORITHM-PROFILES] with
[RFCXXXX] where XXXX is this ID's RFC #. Make the replacements here
and elsewhere in the document. **//
[NIST800-57] National Institute of Standards and Technology, "NIST
Special Publication 800-57, Recommendation for Key Management - Part
1: General (Revised)", NIST Special Publication 800-57, March 2007.
[RFC5652] Housley, R., "Cryptographic Message Syntax (CMS)", RFC
5652, September 2009.
APPENDIX A: ASN.1 Module
This appendix provides the normative ASN.1 definitions for the
structures described in this specification using ASN.1 as defined in
[X.680] through [X.683].
SymmetricKeyPackageModulev1
{ iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
smime(16) modules(0) 33 }
DEFINITIONS IMPLICIT TAGS ::=
BEGIN
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-- EXPORTS ALL
-- IMPORTS NOTHING
PKCS7-CONTENT-TYPE ::= TYPE-IDENTIFIER
KeyPackageContentTypes PKCS7-CONTENT-TYPE ::= {
symmetric-key-package |
... -- Expect additional content types --
}
symmetric-key-package PKCS7-CONTENT-TYPE ::=
{ SymmetricKeyPackage IDENTIFIED BY id-ct-KP-sKeyPackage }
id-ct-KP-sKeyPackage OBJECT IDENTIFIER ::=
{ iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
smime(16) ct(1) 25 }
SymmetricKeyPackage ::= SEQUENCE {
version KeyPkgVersion DEFAULT v1,
sKeyPkgAttrs [0] SEQUENCE SIZE (1..MAX) OF Attribute OPTIONAL,
sKeys SymmetricKeys }
SymmetricKeys ::= SEQUENCE SIZE (1..MAX) OF OneSymmetricKey
OneSymmetricKey ::= SEQUENCE {
sKeyAttrs SEQUENCE SIZE (1..MAX) OF Attribute OPTIONAL,
sKey OCTET STRING OPTIONAL
-- At least sKeyAttrs or sKey MUST be present.
}
KeyPkgVersion ::= INTEGER { v1(1), ... }
Attribute ::= SEQUENCE {
type ATTRIBUTE.&id ({SupportedAttributes}),
values SET SIZE (1..MAX) OF ATTRIBUTE.&Type
({SupportedAttributes}{@type}) }
SupportedAttributes ATTRIBUTE ::= { ... }
ATTRIBUTE ::= CLASS {
&derivation ATTRIBUTE OPTIONAL,
&Type OPTIONAL,
-- either &Type or &derivation required
&equality-match MATCHING-RULE OPTIONAL,
&ordering-match MATCHING-RULE OPTIONAL,
&substrings-match MATCHING-RULE OPTIONAL,
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&single-valued BOOLEAN DEFAULT FALSE,
&collective BOOLEAN DEFAULT FALSE,
-- operational extensions
&no-user-modification BOOLEAN DEFAULT FALSE,
&usage AttributeUsage DEFAULT userApplications,
&id OBJECT IDENTIFIER UNIQUE }
WITH SYNTAX {
[ SUBTYPE OF &derivation ]
[ WITH SYNTAX &Type ]
[ EQUALITY MATCHING RULE &equality-match ]
[ ORDERING MATCHING RULE &ordering-match ]
[ SUBSTRINGS MATCHING RULE &substrings-match ]
[ SINGLE VALUE &single-valued ]
[ COLLECTIVE &collective ]
[ NO USER MODIFICATION &no-user-modification ]
[ USAGE &usage ]
ID &id }
MATCHING-RULE ::= CLASS {
&AssertionType OPTIONAL,
&id OBJECT IDENTIFIER UNIQUE }
WITH SYNTAX {
[ SYNTAX &AssertionType ]
ID &id }
AttributeType ::= ATTRIBUTE.&id
AttributeValue ::= ATTRIBUTE.&Type
AttributeUsage ::= ENUMERATED {
userApplications (0),
directoryOperation (1),
distributedOperation (2),
dSAOperation (3) }
SupportAttributes ATTRIBUTE ::= { ... }
END
PSKCAttributesModule
{ iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
smime(16) modules(0) TBD }
DEFINITIONS IMPLICIT TAGS ::=
BEGIN
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-- EXPORTS ALL
IMPORTS
-- From SymmetricKeyModulev1
ATTRIBUTE
FROM SymmetricKeyPackageModulev1
{ iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
smime(16) modules(0) 33 }
-- From BinaryTime [RFC4049]
BinaryTime
FROM BinarySigningTimeModule
{ iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
smime(16) modules(0) 27 }
;
SupportedAttributes ATTRIBUTE ::= {
at-pskc-manufacturer | at-pskc-serialNo | at-pskc-issueNo |
at-pskc-deviceBinding | at-pskc-startDate | at-pskc-expiryDate |
at-pskc-id | at-pskc-algorithm | at-pskc-issuer |
at-pskc-keyProfileId | at-pskc-friendlyName |
at-pskc-algorithmParameters | at-pskc-counter | at-pskc-time |
at-pskc-timeInterval | at-pskc-timeDrift | at-pskc-valueMAC |
at-pskc-numberOfTransactions | at-pskc-keyUsage |
at-pskc-pinPolicy, ... }
at-pskc-manufacturer ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-manufacturer }
id-pskc-manufacturer OBJECT IDENTIFIER ::= { TBD }
at-pskc-serialNo ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-serialNo }
id-pskc-serialNo OBJECT IDENTIFIER ::= { TBD }
at-pskc-model ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-model }
id-pskc-model OBJECT IDENTIFIER ::= { TBD }
at-pskc-issueNo ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-issueNo }
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id-pskc-issueNo OBJECT IDENTIFIER ::= { TBD }
at-pskc-deviceBinding ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-deviceBinding }
id-pskc-deviceBinding OBJECT IDENTIFIER ::= { TBD }
at-pskc-startDate ATTRIBUTE ::= {
TYPE GeneralizedTime IDENTIFIED BY id-pskc-startDate }
id-pskc-startDate OBJECT IDENTIFIER ::= { TBD }
at-pskc-expiryDate ATTRIBUTE ::= {
TYPE GeneralizedTime IDENTIFIED BY id-pskc-expiryDate }
id-pskc-expiryDate OBJECT IDENTIFIER ::= { TBD }
at-pskc-id ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-id }
id-pskc-id OBJECT IDENTIFIER ::= { TBD }
at-pskc-algorithm ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-algorithm }
id-pskc-algorithm OBJECT IDENTIFIER ::= { TBD }
at-pskc-issuer ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-issuer }
id-pskc-issuer OBJECT IDENTIFIER ::= { TBD }
at-pskc-keyProfileId ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-keyProfileId }
id-pskc-keyProfileId OBJECT IDENTIFIER ::= { TBD }
at-pskc-friendlyName ATTRIBUTE ::= {
TYPE UTF8String IDENTIFIED BY id-pskc-friendlyName }
id-pskc-friendlyName OBJECT IDENTIFIER ::= { TBD }
at-pskc-algorithmParameters ATTRIBUTE ::= {
TYPE PSKCAlgorithmParameters
IDENTIFIED BY id-pskc-algorithmParameters }
id-pskc-algorithmParameters OBJECT IDENTIFIER ::= { TBD }
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PSKCAlgorithmParameters ::= CHOICE {
challengeFormat [0] ChallengeFormat,
responseFormat [1] ResponseFormat,
... }
ChallengeFormat ::= SEQUENCE {
encoding Encoding,
checkDigit BOOLEAN OPTIONAL,
min INTEGER,
max INTEGER,
... }
Encoding ::= CHOICE {
decimal [0] UTF8String ("DECIMAL"),
hexidecimal [1] UTF8String ("HEXIDECIMAL"),
alphanumeric [2] UTF8String ("ALPHANUMERIC"),
base64 [3] UTF8String ("BASE64"),
binary [4] UTF8String ("BINARY") }
ResponseFormat ::= SEQUENCE {
encoding Encoding,
length INTEGER,
checkDigit BOOLEAN OPTIONAL,
... }
at-pskc-counter ATTRIBUTE ::= {
TYPE INTEGER IDENTIFIED BY id-pskc-counter }
id-pskc-counter OBJECT IDENTIFIER ::= { TBD }
at-pskc-time ATTRIBUTE ::= {
TYPE BinaryTime IDENTIFIED BY id-pskc-time }
id-pskc-time OBJECT IDENTIFIER ::= { TBD }
at-pskc-timeInterval ATTRIBUTE ::= {
TYPE BinaryTime IDENTIFIED BY id-pskc-time }
id-pskc-timeInterval OBJECT IDENTIFIER ::= { TBD }
at-pskc-timeDrift ATTRIBUTE ::= {
TYPE BinaryTime IDENTIFIED BY id-pskc-time }
id-pskc-timeDrift OBJECT IDENTIFIER ::= { TBD }
at-pskc-valueMAC ATTRIBUTE ::= {
TYPE ValueMac IDENTIFIED BY id-pskc-valueMAC }
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id-pskc-valueMAC OBJECT IDENTIFIER ::= { TBD }
ValueMac ::= SEQUENCE {
macAlgorithm UTF8String,
mac UTF8String }
at-pskc-numberOfTransactions ATTRIBUTE ::= {
TYPE INTEGER IDENTIFIED BY id-pskc-numberOfTransactions }
id-pskc-numberOfTransactions OBJECT IDENTIFIER ::= { TBD }
at-pskc-keyUsage ATTRIBUTE ::= {
TYPE PSKCKeyUsages IDENTIFIED BY id-pskc-keyUsages }
id-pskc-keyUsages OBJECT IDENTIFIER ::= { TBD }
PSKCKeyUsages ::= SEQUENCE OF PSKCKeyUsage
PSKCKeyUsage ::= CHOICE {
otp [0] UTF8String ("OTP"),
cr [1] UTF8String ("CR"),
encrypt [2] UTF8String ("Encrypt"),
integrity [3] UTF8String ("Integrity"),
verify [4] UTF8String ("Verify"),
unlock [5] UTF8String ("Unlock"),
decrypt [6] UTF8String ("Decrypt"),
keyWrap [7] UTF8String ("KeyWrap"),
unwrap [8] UTF8String ("Unwrap"),
derive [9] UTF8String ("Derive"),
generate [10] UTF8String ("Generate") }
at-pskc-pinPolicy ATTRIBUTE ::= {
TYPE PINPolicy IDENTIFIED BY id-pskc-pinPolicy }
id-pskc-pinPolicy OBJECT IDENTIFIER ::= { TBD }
PINPolicy ::= SEQUENCE {
pinKeyId [0] UTF8String OPTIONAL,
pinUsageMode [1] PINUsageMode,
maxFailedAttempts [2] INTEGER OPTIONAL,
minLength [3] INTEGER OPTIONAL,
maxLength [4] INTEGER OPTIONAL,
pinEncoding [4] Encoding OPTIONAL }
PINUsageMode ::= CHOICE {
local [0] UTF8String ("Local"),
prepend [1] UTF8String ("Prepend"),
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append [2] UTF8String ("Append"),
algorithmic [3] UTF8String ("Algorithmic") }
END
Authors' Address
Sean Turner
IECA, Inc.
3057 Nutley Street, Suite 106
Fairfax, VA 22031
USA
Email: turners@ieca.com
Russ Housley
Vigil Security, LLC
918 Spring Knoll Drive
Herndon, VA 20170
USA
EMail: housley@vigilsec.com
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