Delay-Tolerant Networking E. Birrane
Internet-Draft JHU/APL
Intended status: Experimental J. Mayer
Expires: September 20, 2016 INSYEN AG
D. Iannicca
NASA GRC
March 19, 2016
Bundle Protocol Security Specification
draft-ietf-dtn-bpsec-01
Abstract
This document defines a security protocol providing data integrity
and confidentiality services for the Bundle Protocol. Capabilities
are provided to protect blocks in a bundle along a single path
through a network.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on September 20, 2016.
Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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publication of this document. Please review these documents
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to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Related Documents . . . . . . . . . . . . . . . . . . . . 3
1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
2. Key Properties . . . . . . . . . . . . . . . . . . . . . . . 6
2.1. Block-Level Granularity . . . . . . . . . . . . . . . . . 6
2.2. Multiple Security Sources . . . . . . . . . . . . . . . . 6
2.3. Mixed Security Policy . . . . . . . . . . . . . . . . . . 7
2.4. User-Selected Ciphersuites . . . . . . . . . . . . . . . 8
2.5. Deterministic Processing . . . . . . . . . . . . . . . . 8
3. Security Block Definitions . . . . . . . . . . . . . . . . . 8
3.1. Block Identification . . . . . . . . . . . . . . . . . . 9
3.2. Block Representation . . . . . . . . . . . . . . . . . . 9
3.2.1. CMS Block Type-Specific Data Fields . . . . . . . . . 10
3.2.2. BIB and BCB Block Type-Specific Data Fields . . . . . 10
3.3. Block Ordering . . . . . . . . . . . . . . . . . . . . . 11
3.4. Block Integrity Block . . . . . . . . . . . . . . . . . . 12
3.5. Block Confidentiality Block . . . . . . . . . . . . . . . 13
3.6. Cryptographic Message Syntax Block . . . . . . . . . . . 15
3.7. Block Interactions . . . . . . . . . . . . . . . . . . . 16
3.8. Parameters and Result Fields . . . . . . . . . . . . . . 17
3.9. BSP Block Example . . . . . . . . . . . . . . . . . . . . 19
4. Security Processing . . . . . . . . . . . . . . . . . . . . . 22
4.1. Canonical Forms . . . . . . . . . . . . . . . . . . . . . 22
4.1.1. Block Canonicalization . . . . . . . . . . . . . . . 22
4.1.2. Considerations . . . . . . . . . . . . . . . . . . . 25
4.2. Endpoint ID Confidentiality . . . . . . . . . . . . . . . 25
4.3. Bundles Received from Other Nodes . . . . . . . . . . . . 26
4.3.1. Receiving BCB Blocks . . . . . . . . . . . . . . . . 26
4.3.2. Receiving BIB Blocks . . . . . . . . . . . . . . . . 26
4.4. Receiving CMSB Blocks . . . . . . . . . . . . . . . . . . 27
4.5. Bundle Fragmentation and Reassembly . . . . . . . . . . . 27
4.6. Reactive Fragmentation . . . . . . . . . . . . . . . . . 28
5. Key Management . . . . . . . . . . . . . . . . . . . . . . . 28
6. Policy Considerations . . . . . . . . . . . . . . . . . . . . 28
7. Security Considerations . . . . . . . . . . . . . . . . . . . 29
8. Conformance . . . . . . . . . . . . . . . . . . . . . . . . . 29
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 30
9.1. Bundle Block Types . . . . . . . . . . . . . . . . . . . 30
9.2. Cipher Suite Flags . . . . . . . . . . . . . . . . . . . 30
9.3. Parameters and Results . . . . . . . . . . . . . . . . . 31
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 31
10.1. Normative References . . . . . . . . . . . . . . . . . . 31
10.2. Informative References . . . . . . . . . . . . . . . . . 32
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Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 32
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 32
1. Introduction
This document defines security features for the Bundle Protocol
[BPBIS] intended for use in delay-tolerant networks, in order to
provide Delay-Tolerant Networking (DTN) security services.
The Bundle Protocol is used in DTNs that overlay multiple networks,
some of which may be challenged by limitations such as intermittent
and possibly unpredictable loss of connectivity, long or variable
delay, asymmetric data rates, and high error rates. The purpose of
the Bundle Protocol is to support interoperability across such
stressed networks.
The stressed environment of the underlying networks over which the
Bundle Protocol operates makes it important for the DTN to be
protected from unauthorized use, and this stressed environment poses
unique challenges for the mechanisms needed to secure the Bundle
Protocol. Furthermore, DTNs may be deployed in environments where a
portion of the network might become compromised, posing the usual
security challenges related to confidentiality, integrity, and
availability.
This document describes the Bundle Protocol Security Specification
(BPSec), which provides security services for blocks within a bundle
from the bundle source to the bundle destination. Specifically,
BPSec provides integrity and confidentiality for bundles along a path
through a DTN.
BPSec applies, by definition, only to those nodes that implement it,
known as "security-aware" nodes. There MAY be other nodes in the DTN
that do not implement BPSec. All nodes can interoperate with the
exception that BPSec security operations can only happen at BPSec
security-aware nodes.
1.1. Related Documents
This document is best read and understood within the context of the
following other DTN documents:
"Delay-Tolerant Networking Architecture" [RFC4838] defines the
architecture for delay-tolerant networks, but does not discuss
security at any length.
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The DTN Bundle Protocol [BPBIS] defines the format and processing of
the blocks used to implement the Bundle Protocol, excluding the
security-specific blocks defined here.
The Bundle Security Protocol [RFC6257] and Streamlind Bundle Security
Protocol [SBSP] introduce the concepts of security blocks for
security services. BPSec is based off of these documents.
1.2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
[RFC2119].
We introduce the following terminology for purposes of clarity.
o Source - the bundle node from which a bundle originates.
o Destination - the bundle node to which a bundle is ultimately
destined.
o Forwarder - the bundle node that forwarded the bundle on its most
recent hop.
o Intermediate Receiver, Waypoint, or "Next Hop" - the neighboring
bundle node to which a forwarder forwards a bundle.
o Path - the ordered sequence of nodes through which a bundle passes
on its way from source to destination. The path is not
necessarily known by the bundle, or any bundle-aware nodes.
Figure 1 below is adapted from [BPBIS] and shows four bundle nodes
(denoted BN1, BN2, BN3, and BN4) that reside above some transport
layer(s). Three distinct transport and network protocols (denoted
T1/N1, T2/N2, and T3/N3) are also shown.
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+---------v-| +->>>>>>>>>>v-+ +->>>>>>>>>>v-+ +-^---------+
| BN1 v | | ^ BN2 v | | ^ BN3 v | | ^ BN4 |
+---------v-+ +-^---------v-+ +-^---------v-+ +-^---------+
| T1 v | + ^ T1/T2 v | + ^ T2/T3 v | | ^ T3 |
+---------v-+ +-^---------v-+ +-^---------v + +-^---------+
| N1 v | | ^ N1/N2 v | | ^ N2/N3 v | | ^ N3 |
+---------v-+ +-^---------v + +-^---------v-+ +-^---------+
| >>>>>>>>^ >>>>>>>>>>^ >>>>>>>>^ |
+-----------+ +------------+ +-------------+ +-----------+
| | | |
|<-- An Internet --->| |<--- An Internet --->|
| | | |
Figure 1: Bundle Nodes Sitting at the Application Layer of the
Internet Model
BN1 originates a bundle that it forwards to BN2. BN2 forwards the
bundle to BN3, and BN3 forwards the bundle to BN4. BN1 is the source
of the bundle and BN4 is the destination of the bundle. BN1 is the
first forwarder, and BN2 is the first intermediate receiver; BN2 then
becomes the forwarder, and BN3 the intermediate receiver; BN3 then
becomes the last forwarder, and BN4 the last intermediate receiver,
as well as the destination.
If node BN2 originates a bundle (for example, a bundle status report
or a custodial signal), which is then forwarded on to BN3, and then
to BN4, then BN2 is the source of the bundle (as well as being the
first forwarder of the bundle) and BN4 is the destination of the
bundle (as well as being the final intermediate receiver).
We introduce the following security-specific DTN terminology.
o Security-Service - the security features supported by this
specification: authentication, integrity, and confidentiality.
o Security-Source - a bundle node that adds a security block to a
bundle.
o Security-Target - the portion of a bundle (e.g., the primary
block, payload block, extension block, or entire bundle) that
receives a security-service as part of a security-operation.
o Security Block - a single instance of a BPSec extension block in a
bundle.
o Security-Operation - the application of a security-service to a
specific security-target, notated as OP(security-service,
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security-target). For example, OP(authentication, bundle) or
OP(confidentiality, payload). Every security-operation in a
bundle MUST be unique, meaning that a security-service can only be
applied to a security-target once in a bundle. A security-
operation MAY be implemented by one or more security blocks.
2. Key Properties
The application of security services in a DTN is a complex endeavor
that must consider physical properties of the network, policies at
each node, and various application security requirements. Rather
than enumerate all potential security implementations in all
potential DTN topologies, this specification defines a set of key
properties of a security system. The security primitives outlined in
this document MUST enable the realization of these properties in a
DTN deploying the Bundle Protocol.
2.1. Block-Level Granularity
Blocks within a bundle represent different types of information. The
primary block contains identification and routing information. The
payload block carries application data. Extension blocks carry a
variety of data that may augment or annotate the payload, or
otherwise provide information necessary for the proper processing of
a bundle along a path. Therefore, applying a single level and type
of security across an entire bundle fails to recognize that blocks in
a bundle may represent different types of information with different
security needs.
Security services within this specification MUST provide block level
granularity where applicable such that different blocks within a
bundle may have different security services applied to them.
For example, within a bundle, a payload might be encrypted to protect
its contents, whereas an extension block containing summary
information related to the payload might be integrity signed but
otherwise unencrypted to provide certain nodes access to payload-
related data without providing access to the payload.
2.2. Multiple Security Sources
The Bundle Protocol allows extension blocks to be added to a bundle
at any time during its existence in the DTN. When a waypoint node
adds a new extension block to a bundle, that extension block may have
security services applied to it by that waypoint. Similarly, a
waypoint node may add a security service to an existing extension
block, consistent with its security policy. For example, a node
representing a boundary between a trusted part of the network and an
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untrusted part of the network may wish to apply payload encryption
for bundles leaving the trusted portion of the network.
In each case, a node other than the bundle originator may be adding a
security service to the bundle and, as such, the source for the
security service will be different than the source of the bundle
itself. Security services MUST track their orginating node so as to
properly apply policy and key selection associated with processing
the security service at the bundle destination.
Referring to Figure 1, if the bundle that originates at BN1 is given
security blocks by BN1, then BN1 is the security-source for those
blocks as well as being the source of the bundle. If the bundle that
originates at BN1 is then given a security block by BN2, then BN2 is
the security-source for that block even though BN1 remains the bundle
source.
A bundle MAY have multiple security blocks and these blocks MAY have
different security-sources. Each security block in a bundle will be
associated with a specific security-operation. All security blocks
comprising a security-operation MUST have the same security-source.
As required in [BPBIS], forwarding nodes MUST transmit blocks in a
bundle in the same order in which they were received. This
requirement applies to all DTN nodes, not just ones that implement
security processing. Blocks in a bundle MAY be added or deleted
according to the applicable specification, but those blocks that are
both received and transmitted MUST be transmitted in the same order
that they were received.
2.3. Mixed Security Policy
Different nodes in a DTN may have different security-related
capabilities. Some nodes may not be security-aware and will not
understand any security-related extension blocks. Other nodes may
have security policies that require evaluation of security services
at places other than the bundle destination (such as verifying
integrity signatures at certain waypoint nodes). Other nodes may
ignore any security processing if they are not the destination of the
bundle. The security services described in this specification must
allow each of these scenarios.
Extension blocks representing security services MUST have their block
processing flags set such that the block (and bundle, where
applicable) will be treated appropriately by non-security-aware
nodes.
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Extension blocks providing integrity services within a bundle MUST
support options to allow waypoint nodes to evaluate these signatures
if such nodes have the proper configuraton to do so.
2.4. User-Selected Ciphersuites
The security services defined in this specification rely on a a
variety of ciphersuites providing integrity signatures, ciphertext,
and other information necessary to populate security blocks. Users
may wish to select differing ciphersuites to implement different
security services. For example, some users may wish to use a SHA-1
based hash for integrity whereas other users may require a SHA-2 hash
instead. The security services defined in this specification MUST
provide a mechanism for identifying what ciphersuite has been used to
populate a security block.
2.5. Deterministic Processing
In all cases, the processing order of security services within a
bundle must avoid ambiguity when evaluating security at the bundle
destination. This specification MUST provide determinism in the
application and evaluation of security services, even when doing so
results in a loss of flexibility.
3. Security Block Definitions
There are three types of security blocks that MAY be included in a
bundle. These are the Block Integrity Block (BIB), the Block
Confidentiality Block (BCB), and the Cryptographic Messaging Syntax
Block (CMSB).
The BIB is used to ensure the integrity of its security-target.
The integrity information in the BIB MAY (when possible) be
verified by any node in between the BIB security-source and the
bundle destination. BIBs MAY be added to, and removed from,
bundles as a matter of security policy.
The BCB indicates that the security-target has been encrypted, in
whole or in part, at the BCB security-source in order to protect
its content while in transit. The BCB may be decrypted by
appropriate nodes in the network, up to and including the bundle
destination, as a matter of security policy.
The CMSB contains a Cryptographic Message Syntax (CMS) payload
used to describe a security service applied to another extension
block. NOTE: Applications may choose to simply place CMS text as
the payload to the bundle. In such cases, security is considered
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to be implemented at the application layer and CMSBs are not
required in that case.
Certain cipher suites may allow or require multiple instances of a
block to appear in the bundle. For example, an integrity cipher
suite may require two security blocks, one before the payload block
and one after. Despite the presence of two security blocks, they
both comprise the same security-operation - OP(integirty, target) in
this example.
A security-operation MUST NOT be applied more than once in a bundle.
For example, the two security-operations: OP(integrity, payload) and
OP(integrity, payload) are considered redundant and MUST NOT appear
together in a bundle. However, the two security operations
OP(integrity, payload) and OP(integrity, extension_block_1) MAY both
be present in the bundle. Also, the two security operations
OP(integrity, extension_block_1) and OP(integrity, extension_block_2)
are unique and may both appear in the same bundle.
Many of the fields in these block definitions use the Self-Delimiting
Numeric Value (SDNV) type whose format and encoding is as defined in
[BPBIS].
3.1. Block Identification
This specification requires that every target block of a security
operation be uniquely identifiable. The definition of the extension
block header from [BPBIS] provides such a mechanism in the "block
number", which provides a unique identifier for a block within a
bundle. Within this specification, a target block will be identified
by its unique block number.
3.2. Block Representation
Each security block uses the Canonical Bundle Block Format as defined
in [BPBIS]. That is, each security block is comprised of the
following elements:
o Block Type Code
o Block Number
o Block Processing Control Flags
o Block Data Length
o Block Type Specific Data Fields
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3.2.1. CMS Block Type-Specific Data Fields
The contents of the CMS block is a single field of CMS data whose
length is specified by the BLock Data Length parameter.
3.2.2. BIB and BCB Block Type-Specific Data Fields
The structure of the BIB and BCB type-specific data fields are
identifcal and given in Figure 2. Although the diagram hints at a
fixed-format layout, this is purely for the purpose of exposition.
Except for the "type" field, all fields are variable in length.
Fields annotated with an '*' are optional, with their inclusion in
the block indicated by the cipher suite flags field.
+---------------------------+-------------------------+
| Security Target (SDNV) | Cipher suite ID (SDNV) |
+---------------------------+-------------------------+
| Cipher suite Flags (SDNV) | *Source EID (Compound) |
+---------------------------+-------------------------+
| *Parameters (Compound) | *Sec. Result (Compound) |
+---------------------------+-------------------------+
Figure 2: BIB and BCB Block Structure
The BIB and BCB type-specific data fields consist of the following
fields, some of which are optional.
o Security-Target (SDNV) - Uniquely identifies the target of the
associated security-operation. This MUST be the block number of a
block in the bundle.
o Cipher suite ID (SDNV) - Identifies the ciphersuite used to
implement the security service reprsented by this block.
o Cipher suite flags (SDNV) - Identifies which optional security
block fields are present in the block. The structure of the
cipher suite flags field is shown in Figure 3. The presence of an
optional field is indicated by setting the value of the
corresponding flag to one. A value of zero indicates the
corresponding optional field is not present. The BPSEC cipher
suite flags are defined as follows.
* bits 6-3 are reserved for future use.
* src - bit 2 indicates whether the security source EID is
present in the block. This identifief the EID that inserted
the security service in the bundle. If the security source is
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not present then the souce of the block MAY be taken to be the
bundle source, the previous hop, or some other EID as defined
by security policy.
* parm - bit 1 indicates whether or not the cipher suite
parameters fields are present in the block.
* res - bit 0 indicates whether or not the security result fields
are present in the block.
Bit Bit Bit Bit Bit Bit Bit
6 5 4 3 2 1 0
+-----+-----+-----+-----+-----+-----+-----+
| reserved | src |parm | res |
+-----+-----+-----+-----+-----+-----+-----+
Figure 3: Cipher suite flags
o (OPTIONAL) Parameters - compound field of the following two items.
* Length (SDNV) - specifies the length of the next field, which
captures the parameters data.
* Data - A byte array encoding one or more cipher suite
parameters, with each parameter represented as a Type-Length-
Value (TLV) triplet. In this triplet, the type and length are
represented as SDNVs and the value is a byte array holding the
parmeter. See Section 3.8 for a list of parameter types that
MUST be supported by BPSEC implementations. BPSEC cipher suite
specifications MAY define their own parameters to be
represented in this byte array.
o (OPTIONAL) Security Result - compound field of the next two items.
* Length (SDNV) - specifies the length of the next field, which
is the security-result data.
* Data - A byte array containing the results of the appropriate
cipher suite specific calculation (e.g., a signature, Message
Authentication Code (MAC), or cipher-text block key).
3.3. Block Ordering
A security-operation may be implemented in a bundle using either one
or two security blocks. For example, the operation OP(integrity,
block) MAY be accomplished by a single BIB block in the bundle, or it
MAY be accomplished by two BIB blocks in the bundle. To avoid
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confusion, we use the following terminology to identify the block or
blocks comprising a security-operation.
The terms "First" and "Last" are used ONLY when describing multiple
security blocks comprising a single security-operation. A "First"
block refers to the security block that is closest to the primary
block in the canonical form of the bundle. A "Last" block refers to
the security block that is furthest from the primary block in the
canonical form of the bundle.
If a single security block implements the security-operation, then it
is referred to as a "Lone" block. For example, when a bundle
authentication cipher suite requires a single BIB block we refer to
it as a Lone BAB. When a bundle authentication cipher suite requires
two BIB blocks we refer to them as the First BIB and the Last BIB.
This specification and individual cipher suites impose restrictions
on what optional fields must and must not appear in First blocks,
Last blocks, and Lone blocks.
3.4. Block Integrity Block
A BIB is an ASB with the following additional restrictions:
The block-type code value MUST be 0x02.
The block processing control flags value can be set to whatever
values are required by local policy. Cipher suite designers
should carefully consider the effect of setting flags that either
discard the block or delete the bundle in the event that this
block cannot be processed.
The security-target MUST match the BLock Number of a block within
the bundle. The security-target for a BIB MUST NOT reference a
security block defined in this specification (BIB, BCB, or CMSB).
The cipher suite ID MUST be documented as an end-to-end
authentication-cipher suite or as an end-to-end error-detection-
cipher suite.
The cipher suite parameters field MAY be present in either a Lone
BIB or a First BIB. This field MUST NOT be present in a Last BIB.
An EID-reference to the security-source MAY be present in either a
Lone BIB or a First BIB. This field MUST NOT be present in a Last
BIB.
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The security-result captures the result of applying the cipher
suite calculation (e.g., the MAC or signature) to the relevant
parts of the security-target, as specified in the cipher suite
definition. This field MUST be present in either a Lone BIB or a
Last BIB. This field MUST NOT be present in a First BIB.
The cipher suite MAY process less than the entire security-target.
If the cipher suite processes less than the complete, original
security-target, the cipher suite parameters MUST specify which
bytes of the security-target are protected.
Notes:
o Since OP(integrity, target) is allowed only once in a bundle per
target, it is RECOMMENDED that users wishing to support multiple
integrity signatures for the same target define a multi-signature
cipher suite, capturing multiple security results in cipher suite
parameters.
o For some cipher suites, (e.g., those using asymmetric keying to
produce signatures or those using symmetric keying with a group
key), the security information MAY be checked at any hop on the
way to the destination that has access to the required keying
information, in accordance with Section 3.7.
o The use of a generally available key is RECOMMENDED if custodial
transfer is employed and all nodes SHOULD verify the bundle before
accepting custody.
3.5. Block Confidentiality Block
A BCB is an ASB with the following additional restrictions:
The block-type code value MUST be 0x03.
The block processing control flags value can be set to whatever
values are required by local policy, except that a Lone BCB or
First BCB MUST have the "replicate in every fragment" flag set.
This indicates to a receiving node that the payload portion in
each fragment represents cipher-text. This flag SHOULD NOT be set
otherwise. Cipher suite designers should carefully consider the
effect of setting flags that either discard the block or delete
the bundle in the event that this block cannot be processed.
The security-target MUST match the BLock Number of a block within
the bundle. The security-target for a BCB MAY reference the
payload block, a non-security extension block, or a BIB block.
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The cipher suite ID MUST be documented as a confidentiality cipher
suite.
Key-information, if available, MUST appear only in a Lone BCB or a
First BCB.
Any additional bytes generated as a result of encryption and/or
authentication processing of the security-target SHOULD be placed
in an "integrity check value" field (see Section 3.8) in the
security-result of the Lone BCB or Last BCB.
The cipher suite parameters field MAY be present in either a Lone
BCB or a First BCB. This field MUST NOT be present in a Last BCB.
An EID-reference to the security-source MAY be present in either a
Lone BCB or a First BCB. This field MUST NOT be present in a Last
BCB. The security-source can also be specified as part of key-
information described in Section 3.8.
The security-result MAY be present in either a Lone BCB or a Last
BCB. This field MUST NOT be present in a First BCB. This
compound field normally contains fields such as an encrypted
bundle encryption key and/or authentication tag.
The BCB is the only security block that modifies the contents of its
security-target. When a BCB is applied, the security-target body
data are encrypted "in-place". Following encryption, the security-
target body data contains cipher-text, not plain-text. Other
security-target block fields (such as type, processing control flags,
and length) remain unmodified.
Fragmentation, reassembly, and custody transfer are adversely
affected by a change in size of the payload due to ambiguity about
what byte range of the block is actually in any particular fragment.
Therefore, when the security-target of a BCB is the bundle payload,
the BCB MUST NOT alter the size of the payload block body data.
Cipher suites SHOULD place any block expansion, such as
authentication tags (integrity check values) and any padding
generated by a block-mode cipher, into an integrity check value item
in the security-result field (see Section 3.8) of the BCB. This "in-
place" encryption allows fragmentation, reassembly, and custody
transfer to operate without knowledge of whether or not encryption
has occurred.
Notes:
o The cipher suite MAY process less than the entire original
security-target body data. If the cipher suite processes less
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than the complete, original security-target body data, the BCB for
that security-target MUST specify, as part of the cipher suite
parameters, which bytes of the body data are protected.
o The BCB's "discard" flag may be set independently from its
security-target's "discard" flag. Whether or not the BCB's
"discard" flag is set is an implementation/policy decision for the
encrypting node. (The "discard" flag is more properly called the
"Discard if block cannot be processed" flag.)
o A BCB MAY include information as part of additional authenticated
data to address parts of the target block, such as EID references,
that are not converted to cipher-text.
3.6. Cryptographic Message Syntax Block
A CMSB is an ASB with the following additional restrictions:
The block-type code value MUST be 0x04.
The content of the block must contain valid CMS data, as defined
in [RFC5652] , and encoded in X.690 BER or DER encoding.
The block processing control flags value can be set to whatever
values are required by local policy. This flag SHOULD NOT be set
otherwise. Cipher suite designers should carefully consider the
effect of setting flags that either discard the block or delete
the bundle in the event that this block cannot be processed.
The security-target MUST uniquely identify a block within the
bundle. The reserved block type 0x01 specifies the singleton
payload block.
The security operation(s) will be performed on the security-target
block's data and the resulting CMS content will be stored within
the CMSB block's security-result field. The security-target
block's data will then be removed.
A CMSB block MAY include multiple CMS security operations within a
single block to allow for multiple nested operations to be
performed on a bundle block. Multiple CMSB blocks MAY be included
in a bundle as long as the security-target for each is unique.
Key-information, if available, MUST appear within the CMS content
contained in the security-result field.
A CMSB block is created with its corresponding security-target field
pointing to a unique bundle block. The CMS security operations are
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performed upon the security-target's data field and the resulting
encoded CMS content is stored within the CMS security-result field of
the CMSB's payload. The security-target block's data MAY be left
intact, replaced with alternate data, or completely erased based on
the specification of the utilized CMS ciphersuite definition and
applicable policy.
Multiple CMS operations may be nested within a single CMSB block to
allow more than one security operation to be performed upon a
security-target.
CMS Operations can be considered to have BPSec parallels: CMSB
Enveloped-Data content type SHALL be considered as equivalent to a
BPSec BCB block, and a CMSB Signed-Data type SHALL be considered as
equivalent to a BPSec BIB block.
3.7. Block Interactions
The security-block types defined in this specification are designed
to be as independent as possible. However, there are some cases
where security blocks may share a security-target creating processing
dependencies.
If confidentiality is being applied to a target that already has
integrity applied to it, then an undesirable condition occurs where a
security-aware intermediate node would be unable to check the
integrity result of a block because the block contents have been
encrypted after the integrity signature was generated. To address
this concern, the following processing rules MUST be followed.
o If confidentiality is to be applied to a target, it MUST also be
applied to every integrity operation already defined for that
target. This means that if a BCB is added to encrypt a block,
another BCB MUST also be added to encrypt a BIB also targeting
that block.
o An integrity operation MUST NOT be applied to a security-target if
a BCB in the bundle shares the same security-target. This
prevents ambiguity in the order of evaluation when receiving a BIB
and a BCB for a given security-target.
o An integrity value MUST NOT be evaluated if the BIB providing the
integrity value is the security target of an existing BCB block in
the bundle. In such a case, the BIB data contains cipher-text as
it has been encrypted.
o An integrity value MUST NOT be evaluated if the security-target of
the BIB is also the security-target of a BCB in the bundle. In
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such a case, the security-target data contains cipher-text as it
has been encrypted.
o As mentioned in Section 3.5, a BIB MUST NOT have a BCB as its
security target. BCBs may embed integrity results as part of
cipher suite parameters.
o As mentioned in Section 4.4, CMS operations are considered to have
operational parallels. When a CMSB is used, these parallels MUST
be considered for block interactions (e.g., a Signed-Data
structure MUST NOT be evaluated if the security-target of the
operation is also the security-target of a BCB)
o If a single bundle is going to contain a CMSB as well as other
security blocks, the CMS operations MUST be performed and the CMSB
MUST be created before any other security operation is applied.
Additionally, since the CMSB block may contain either integrity or
confidentiality information in its encapsulated CMS, there is no way
to evaluate conflicts when a BIB/BCB and a CMSB have the same
security target. To address this concern, the following processing
rules MUST be followed.
o If an extension block is the target of a BIB or a BCB, then the
extension block MUST NOT also be the target of a CMSB, and vice-
versa.
o Generally, a CMSB MUST be processed before any BIB or BCB blocks
are processed.
These restrictions on block interactions impose a necessary ordering
when applying security operations within a bundle. Specifically, for
a given security-target, BIBs MUST be added before BCBs. This
ordering MUST be preserved in cases where the current BPA is adding
all of the security blocks for the bundle or whether the BPA is a
waypoint adding new security blocks to a bundle that already contains
security blocks.
3.8. Parameters and Result Fields
Various cipher suites include several items in the cipher suite
parameters and/or security-result fields. Which items MAY appear is
defined by the particular cipher suite description. A cipher suite
MAY support several instances of the same type within a single block.
Each item is represented as a type-length-value. Type is a single
byte indicating the item. Length is the count of data bytes to
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follow, and is an SDNV-encoded integer. Value is the data content of
the item.
Item types, name, and descriptions are defined as follows.
Cipher suite parameters and result fields.
+-------+----------------+------------------------------------------+
| Type | Name | Description |
+-------+----------------+------------------------------------------+
| 0 | Reserved | |
+-------+----------------+------------------------------------------+
| 1 | Initialization | A random value, typically eight to |
| | Vector (IV) | sixteen bytes. |
+-------+----------------+------------------------------------------+
| 2 | Reserved | |
+-------+----------------+------------------------------------------+
| 3 | Key | Material encoded or protected by the key |
| | Information | management system and used to transport |
| | | an ephemeral key protected by a long- |
| | | term key. |
+-------+----------------+------------------------------------------+
| 4 | Content Range | Pair of SDNV values (offset,length) |
| | | specifying the range of payload bytes to |
| | | which an operation applies. The offset |
| | | MUST be the offset within the original |
| | | bundle, even if the current bundle is a |
| | | fragment. |
+-------+----------------+------------------------------------------+
| 5 | Integrity | Result of BAB or BIB digest or other |
| | Signatures | signing operation. |
+-------+----------------+------------------------------------------+
| 6 | Unassigned | |
+-------+----------------+------------------------------------------+
| 7 | Salt | An IV-like value used by certain |
| | | confidentiality suites. |
+-------+----------------+------------------------------------------+
| 8 | BCB Integrity | Output from certain confidentiality |
| | Check Value | cipher suite operations to be used at |
| | (ICV) / | the destination to verify that the |
| | Authentication | protected data has not been modified. |
| | Tag | This value MAY contain padding if |
| | | required by the cipher suite. |
+-------+----------------+------------------------------------------+
| 9-255 | Reserved | |
+-------+----------------+------------------------------------------+
Table 1
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3.9. BSP Block Example
An example of BPSec blocks applied to a bundle is illustrated in
Figure 4. In this figure the first column represents blocks within a
bundle and the second column represents a unique identifier for each
block, suitable for use as the security-target of a BPSec security-
block. Since the mechanism and format of a security-target is not
specified in this document, the terminology B1...Bn is used to
identify blocks in the bundle for the purposes of illustration.
Block in Bundle ID
+=================================+====+
| Primary Block | B1 |
+---------------------------------+----+
| Lone BIB | B2 |
| OP(integrity, target=B1) | |
+---------------------------------+----+
| Lone BCB | B3 |
| OP(confidentiality, target=B4) | |
+---------------------------------+----+
| Extension Block | B4 |
+---------------------------------+----+
| Lone BIB | B5 |
| OP(integrity, target=B6) | |
+---------------------------------+----+
| Extension Block | B6 |
+---------------------------------+----+
| Lone BCB | B7 |
| OP(confidentiality, target=B8) | |
+---------------------------------+----+
| Lone BIB (encrypted by B7) | B8 |
| OP(integrity, target=B10) | |
+---------------------------------+----|
| Lone BCB | B9 |
| OP(confidentiality, target=B10) | |
+---------------------------------+----+
| Payload Block |B10 |
+---------------------------------+----+
Figure 4: Sample Use of BSP Blocks
In this example a bundle has five non-security-related blocks: the
primary block (B1), three extension blocks (B4,B6,B9), and a payload
block (B11). The following security applications are applied to this
bundle.
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o An integrity signature applied to the canonicalized primary block.
This is accomplished by a single BIB (B2).
o Confidentiality for the first extension block (B4). This is
accomplished by a single BCB block (B3).
o Integrity for the second extension block (B6). This is
accomplished by a single BIB block (B5). NOTE: If the extension
block B6 contains a representation of the serialized bundle (such
as a hash over all blocks in the bundle at the time of its last
transmission) then the BIB block is also providing an
authentication service from the prior BPSEC-BPA to this BPSEC-BPA.
o An integrity signature on the payload (B10). This is accomplished
by a single BIB block (B8).
o Confidentiality for the payload block and it's integrity
signature. This is accomplished by two Lone BCB blocks: B7
encrypting B8, and B9 encrypting B10.
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Block in Bundle ID
+=========================================+====+
| Primary Block | B1 |
+-----------------------------------------+----+
| First BAB | B2 |
| OP(authentication, Bundle) | |
+-----------------------------------------+----+
| Lone CMSB | B3 |
| security-target=0x01 | |
| security-result= | |
| | |
| Signed-Data { | |
| Digest Algorithm(s), | |
| Enveloped-Data { | |
| Encrypted Data, | |
| Encrypted Encryption Key(s) | |
| }, | |
| Signature(s) and Certificate Chain(s) | |
| } | |
| | |
+-----------------------------------------+----+
| Payload Block | B4 |
| (Empty Data Field) | |
+-----------------------------------------+----+
| Last BAB | B5 |
| OP(authentication, Bundle) | |
+-----------------------------------------+----+
Figure 5: Sample Bundle With CMS Block
In this example a bundle has two non-security-related blocks: the
primary block (B1) and a payload block (B4). This method would allow
for the bundle to carry multiple CMS payloads by utilizing a multiple
CMSB ASBs. The following security applications are applied to this
bundle.
o Authentication over the bundle. This is accomplished by two BAB
blocks: B2 and B5.
o Encrypted and signed CMS content contained within the CMSB block.
The first CMS operation, encryption, is performed on the data
contained within the block the security-target points to, in this
case, the payload block. The resulting encrypted data is then
signed and the final CMS content is stored within the CMSB block's
security-result field. The payload block's data is subsequently
removed now that the original data has been encoded within the
CMSB block.
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4. Security Processing
This section describes the security aspects of bundle processing.
4.1. Canonical Forms
In order to verify a signature of a block, the exact same bits, in
the exact same order, MUST be input to the calculation upon
verification as were input upon initial computation of the original
signature value.
Many fields in various blocks are stored as variable-length SDNVs.
These are canonicalized into an "unpacked form" as eight-byte fixed-
width fields in network byte order.
4.1.1. Block Canonicalization
This algorithm protects those parts of a block that SHOULD NOT be
changed in transit.
There are three types of blocks that may undergo block
canonicalization: the primary block, the payload block, or an
extension block.
4.1.1.1. Primary Block Canonicalization
The canonical form of the primary block is shown in Figure 6.
Essentially, it de-references the dictionary block, adjusts lengths
where necessary, and ignores flags that may change in transit.
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+----------------+----------------+----------------+----------------+
| Version | Processing flags (incl. COS and SRR) |
+----------------+----------------+---------------------------------+
| Canonical primary block length |
+----------------+----------------+---------------------------------+
| Destination endpoint ID length |
+----------------+----------------+---------------------------------+
| Destination endpoint ID |
+----------------+----------------+---------------------------------+
| Source endpoint ID length |
+----------------+----------------+----------------+----------------+
| Source endpoint ID |
+----------------+----------------+---------------------------------+
| Report-to endpoint ID length |
+----------------+----------------+----------------+----------------+
| Report-to endpoint ID |
+----------------+----------------+----------------+----------------+
+ Creation Timestamp (2 x SDNV) +
+---------------------------------+---------------------------------+
| Lifetime |
+----------------+----------------+----------------+----------------+
Figure 6: The Canonical Form of the Primary Bundle Block
The fields shown in Figure 6 are as follows:
o The version value is the single-byte value in the primary block.
o The processing flags value in the primary block is an SDNV, and
includes the class-of-service (COS) and status report request
(SRR) fields. For purposes of canonicalization, the unpacked SDNV
is ANDed with mask 0x0000 0000 0007 C1BE to set to zero all
reserved bits and the "bundle is a fragment" bit.
o The canonical primary block length value is a four-byte value
containing the length (in bytes) of this structure, in network
byte order.
o The destination endpoint ID length and value are the length (as a
four-byte value in network byte order) and value of the
destination endpoint ID from the primary bundle block. The URI is
simply copied from the relevant part(s) of the dictionary block
and is not itself canonicalized. Although the dictionary entries
contain "null-terminators", the null-terminators are not included
in the length or the canonicalization.
o The source endpoint ID length and value are handled similarly to
the destination.
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o The report-to endpoint ID length and value are handled similarly
to the destination.
o The unpacked SDNVs for the creation timestamp and lifetime are
copied from the primary block.
o Fragment offset and total application data unit length are
ignored, as is the case for the "bundle is a fragment" bit
mentioned above. If the payload data to be canonicalized is less
than the complete, original bundle payload, the offset and length
are specified in the cipher suite parameters.
4.1.1.2. Payload Block Canonicalization
When canonicalizing the payload block, the block processing control
flags value used for canonicalization is the unpacked SDNV value with
reserved and mutable bits masked to zero. The unpacked value is
ANDed with mask 0x0000 0000 0000 0077 to zero reserved bits and the
"last block" bit. The "last block" bit is ignored because BABs and
other security blocks MAY be added for some parts of the journey but
not others, so the setting of this bit might change from hop to hop.
Payload blocks are canonicalized as-is, with the exception that, in
some instances, only a portion of the payload data is to be
protected. In such a case, only those bytes are included in the
canonical form, and additional cipher suite parameters are required
to specify which part of the payload is protected, as discussed
further below.
4.1.1.3. Extension Block Canonicalization
When canonicalizing an extension block, the block processing control
flags value used for canonicalization is the unpacked SDNV value with
reserved and mutable bits masked to zero. The unpacked value is
ANDed with mask 0x0000 0000 0000 0057 to zero reserved bits, the
"last block" flag and the "Block was forwarded without being
processed" bit. The "last block" flag is ignored because BABs and
other security blocks MAY be added for some parts of the journey but
not others, so the setting of this bit might change from hop to hop.
The "Block was forwarded without being processed" flag is ignored
because the bundle may pass through nodes that do not understand that
extension block and this flag would be set.
Endpoint ID references in blocks are canonicalized using the de-
referenced text form in place of the reference pair. The reference
count is not included, nor is the length of the endpoint ID text.
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The EID reference is, therefore, canonicalized as <scheme>:<SSP>,
which includes the ":" character.
Since neither the length of the canonicalized EID text nor a null-
terminator is used in EID canonicalization, a separator token MUST be
used to determine when one EID ends and another begins. When
multiple EIDs are canonicalized together, the character "," SHALL be
placed between adjacent instances of EID text.
The block-length is canonicalized as its unpacked SDNV value. If the
data to be canonicalized is less than the complete, original block
data, this field contains the size of the data being canonicalized
(the "effective block") rather than the actual size of the block.
4.1.2. Considerations
o The canonical forms for the bundle and various extension blocks is
not transmitted. It is simply an artifact used as input to
digesting.
o We omit the reserved flags because we cannot determine if they
will change in transit. The masks specified above will have to be
revised if additional flags are defined and they need to be
protected.
o All SDNV fields here are canonicalized as eight-byte unpacked
values in network byte order. Length fields are canonicalized as
four-byte values in network byte order. Encoding does not need
optimization since the values are never sent over the network.
o These canonicalization algorithms assume that endpoint IDs
themselves are immutable and they are unsuitable for use in
environments where that assumption might be violated.
o Cipher suites MAY define their own canonicalization algorithms and
require the use of those algorithms over the ones provided in this
specification.
4.2. Endpoint ID Confidentiality
Every bundle has a primary block that contains the source and
destination endpoint IDs, and possibly other EIDs (in the dictionary
field) that cannot be encrypted. If endpoint ID confidentiality is
required, then bundle-in-bundle encapsulation can solve this problem
in some instances.
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Similarly, confidentiality requirements MAY also apply to other parts
of the primary block (e.g., the current-custodian), and that is
supported in the same manner.
4.3. Bundles Received from Other Nodes
Security blocks MUST be processed in a specific order when received
by a security-aware node. The processing order is as follows.
o All BCB blocks in the bundle MUST be evaluated prior to evaluating
any BIBs in the bundle. When BIBs and BCBs share a security-
target, BCBs MUST be evaluated first and BIBs second.
4.3.1. Receiving BCB Blocks
If the bundle has a BCB and the receiving node is the destination for
the bundle, the node MUST decrypt the relevant parts of the security-
target in accordance with the cipher suite specification.
If the relevant parts of an encrypted payload cannot be decrypted
(i.e., the decryption key cannot be deduced or decryption fails),
then the bundle MUST be discarded and processed no further; in this
case, a bundle deletion status report (see [BPBIS]) indicating the
decryption failure MAY be generated. If any other encrypted
security-target cannot be decrypted then the associated security-
target and all security blocks associated with that target MUST be
discarded and processed no further.
When a BCB is decrypted, the recovered plain-text MUST replace the
cipher-text in the security-target body data
4.3.2. Receiving BIB Blocks
A BIB MUST NOT be processed if the security-target of the BIB is also
the security-target of a BCB in the bundle. Given the order of
operations mandated by this specification, when both a BIB and a BCB
share a security-target, it means that the security-target MUST have
been encrypted after it was integrity signed and, therefore, the BIB
cannot be verified until the security-target has been decrypted by
processing the BCB.
If the security policy of a security-aware node specifies that a
bundle SHOULD apply integrity to a specific security-target and no
such BIB is present in the bundle, then the node MUST process this
security-target in accordance with the security policy. This MAY
involve removing the security-target from the bundle. If the removed
security-target is the payload or primary block, the bundle MAY be
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discarded. This action may occur at any node that has the ability to
verify an integrity signature, not just the bundle destination.
If the bundle has a BIB and the receiving node is the destination for
the bundle, the node MUST verify the security-target in accordance
with the cipher suite specification. If a BIB check fails, the
security-target has failed to authenticate and the security-target
SHALL be processed according to the security policy. A bundle status
report indicating the failure MAY be generated. Otherwise, if the
BIB verifies, the security-target is ready to be processed for
delivery.
If the bundle has a BIB and the receiving node is not the bundle
destination, the receiving node MAY attempt to verify the value in
the security-result field. If the check fails, the node SHALL
process the security-target in accordance to local security policy.
It is RECOMMENDED that if a payload integrity check fails at a
waypoint that it is processed in the same way as if the check fails
at the destination.
4.4. Receiving CMSB Blocks
A CMSB MUST NOT be processed if its security target is also the
security target of any BIB or BCB in the bundle.
The security services provided by a CMSB will be considered
successful if all services in the CMSB are validated. If any one
service encapsulated in the CMSB fails to validate, then the CMSB
MUST be considered as having failed to validate and MUST be
dispositioned in accordance with security policy.
4.5. Bundle Fragmentation and Reassembly
If it is necessary for a node to fragment a bundle and security
services have been applied to that bundle, the fragmentation rules
described in [BPBIS] MUST be followed. As defined there and repeated
here for completeness, only the payload may be fragmented; security
blocks, like all extension blocks, can never be fragmented. In
addition, the following security-specific processing is REQUIRED:
o Due to the complexity of bundle fragmentation, including the
possibility of fragmenting bundle fragments, integrity and
confidentiality operations are not to be applied to a bundle
fragment. Specifically, a BCB or BIB MUST NOT be added to a
bundle fragment, even if the security-target of the security block
is not the payload. When integrity and confidentiality must be
applied to a fragment, we RECOMMEND that encapsulation be used
instead.
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o The authentication security policy requirements for a bundle MUST
be applied individually to all the bundles resulting from a
fragmentation event.
o The decision to fragment a bundle MUST be made prior to adding
authentication to the bundle. The bundle MUST first be fragmented
and authentication applied to each individual fragment.
4.6. Reactive Fragmentation
When a partial bundle has been received, the receiving node SHALL
consult its security policy to determine if it MAY fragment the
bundle, converting the received portion into a bundle fragment for
further forwarding. Whether or not reactive fragmentation is
permitted SHALL depend on the security policy and the cipher suite
used to calculate the BAB authentication information, if required.
Specifically, if the security policy does not require authentication,
then reactive fragmentation MAY be permitted. If the security policy
does require authentication, then reactive fragmentation MUST NOT be
permitted if the partial bundle is not sufficient to allow
authentication.
If reactive fragmentation is allowed, then all BAB blocks must be
removed from created fragments.
5. Key Management
Key management in delay-tolerant networks is recognized as a
difficult topic and is one that this specification does not attempt
to solve.
6. Policy Considerations
When implementing BPSec, several policy decisions must be considered.
This section describes key policies that affect the generation,
forwarding, and receipt of bundles that are secured using this
specification.
o If a bundle is received that contains more than one security-
operation, in violation of BPSec, then the BPA must determine how
to handle this bundle. The bundle may be discarded, the block
affected by the security-operation may be discarded, or one
security-operation may be favored over another.
o BPAs in the network MUST understand what security-operations they
should apply to bundles. This decision may be based on the source
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of the bundle, the destination of the bundle, or some other
information related to the bundle.
o If an intermediate receiver has been configured to add a security-
operation to a bundle, and the received bundle already has the
security-operation applied, then the receiver MUST understand what
to do. The receiver may discard the bundle, discard the security-
target and associated BPSec blocks, replace the security-
operation, or some other action.
o It is recommended that security operations only be applied to the
payload block, the primary block, and any block-types specifically
identified in the security policy. If a BPA were to apply
security operations such as integrity or confidentiality to every
block in the bundle, regardless of the block type, there could be
downstream errors processing blocks whose contents must be
inspected at every hop in the network path.
7. Security Considerations
Certain applications of DTN need to both sign and encrypt a message,
and there are security issues to consider with this.
o To provide an assurance that a security-target came from a
specific source and has not been changed, then it should be signed
with a BIB.
o To ensure that a security-target cannot be inspected during
transit, it should be encrypted with a BCB.
o Adding a BIB to a security-target that has already been encrypted
by a BCB is not allowed. Therefore, we recommend three methods to
add an integrity signature to an encrypted security-target.
First, at the time of encryption, an integrity signature may be
generated and added to the BCB for the security-target as
additional information in the security-result field. Second, the
encrypted block may be replicated as a new block and integrity
signed. Third, an encapsulation scheme may be applied to
encapsulate the security-target (or the entire bundle) such that
the encapsulating structure is, itself, no longer the security-
target of a BCB and may therefore be the security-target of a BIB.
8. Conformance
All implementations are strongly RECOMMENDED to provide some method
of hop-by-hop verification by generating a hash to some canonical
form of the bundle and placing an integrity signature on that form
using a BIB.
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9. IANA Considerations
This protocol has fields that have been registered by IANA.
9.1. Bundle Block Types
This specification allocates three block types from the existing
"Bundle Block Types" registry defined in [RFC6255] .
Additional Entries for the Bundle Block-Type Codes Registry:
+-------+-----------------------------+---------------+
| Value | Description | Reference |
+-------+-----------------------------+---------------+
| 2 | Block Integrity Block | This document |
| 3 | Block Confidentiality Block | This document |
| 4 | CMS Block | This document |
+-------+-----------------------------+---------------+
Table 2
9.2. Cipher Suite Flags
This protocol has a cipher suite flags field and certain flags are
defined. An IANA registry has been set up as follows.
The registration policy for this registry is: Specification Required
The Value range is: Variable Length
Cipher Suite Flag Registry:
+--------------------------+-------------------------+--------------+
| Bit Position (right to | Description | Reference |
| left) | | |
+--------------------------+-------------------------+--------------+
| 0 | Block contains result | This |
| | | document |
| 1 | Block Contains | This |
| | parameters | document |
| 2 | Source EID ref present | This |
| | | document |
| >3 | Reserved | This |
| | | document |
+--------------------------+-------------------------+--------------+
Table 3
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9.3. Parameters and Results
This protocol has fields for cipher suite parameters and results.
The field is a type-length-value triple and a registry is required
for the "type" sub-field. The values for "type" apply to both the
cipher suite parameters and the cipher suite results fields. Certain
values are defined. An IANA registry has been set up as follows.
The registration policy for this registry is: Specification Required
The Value range is: 8-bit unsigned integer.
Cipher Suite Parameters and Results Type Registry:
+---------+---------------------------------+---------------+
| Value | Description | Reference |
+---------+---------------------------------+---------------+
| 0 | reserved | This document |
| 1 | initialization vector (IV) | This document |
| 2 | reserved | This document |
| 3 | key-information | This document |
| 4 | content-range (pair of SDNVs) | This document |
| 5 | integrity signature | This document |
| 6 | unassigned | This document |
| 7 | salt | This document |
| 8 | BCB integrity check value (ICV) | This document |
| 9-191 | reserved | This document |
| 192-250 | private use | This document |
| 251-255 | reserved | This document |
+---------+---------------------------------+---------------+
Table 4
10. References
10.1. Normative References
[BPBIS] Burleigh, S., Fall, K., and E. Birrane, "Bundle Protocol",
draft-ietf-dtn-bpbis-03 (work in progress), March 2016.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5652] Housley, R., "Cryptographic Message Syntax (CMS)", STD 70,
RFC 5652, DOI 10.17487/RFC5652, September 2009,
<http://www.rfc-editor.org/info/rfc5652>.
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[RFC6255] Blanchet, M., "Delay-Tolerant Networking Bundle Protocol
IANA Registries", RFC 6255, May 2011.
10.2. Informative References
[RFC4838] Cerf, V., Burleigh, S., Hooke, A., Torgerson, L., Durst,
R., Scott, K., Fall, K., and H. Weiss, "Delay-Tolerant
Networking Architecture", RFC 4838, April 2007.
[RFC6257] Symington, S., Farrell, S., Weiss, H., and P. Lovell,
"Bundle Security Protocol Specification", RFC 6257, May
2011.
[SBSP] Birrane, E., "Streamlined Bundle Security Protocol",
draft-birrane-dtn-sbsp-01 (work in progress), October
2015.
Appendix A. Acknowledgements
The following participants contributed technical material, use cases,
and useful thoughts on the overall approach to this security
specification: Scott Burleigh of the Jet Propulsion Laboratory, Amy
Alford and Angela Hennessy of the Laboratory for Telecommunications
Sciences, and Angela Dalton and Cherita Corbett of the Johns Hopkins
University Applied Physics Laboratory.
Authors' Addresses
Edward J. Birrane, III
The Johns Hopkins University Applied Physics Laboratory
11100 Johns Hopkins Rd.
Laurel, MD 20723
US
Phone: +1 443 778 7423
Email: Edward.Birrane@jhuapl.edu
Jeremy Pierce-Mayer
INSYEN AG
Muenchner Str. 20
Oberpfaffenhofen, Bavaria DE
Germany
Phone: +49 08153 28 2774
Email: jeremy.mayer@insyen.com
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Dennis C. Iannicca
NASA Glenn Research Center
21000 Brookpark Rd.
Brook Park, OH 44135
US
Phone: +1-216-433-6493
Email: dennis.c.iannicca@nasa.gov
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