rfc:rfc6622
Internet Engineering Task Force (IETF) U. Herberg Request for Comments: 6622 Fujitsu Laboratories of America Category: Standards Track T. Clausen ISSN: 2070-1721 LIX, Ecole Polytechnique
May 2012
Integrity Check Value and Timestamp TLV Definitions
for Mobile Ad Hoc Networks (MANETs)
Abstract
This document describes general and flexible TLVs for representing cryptographic Integrity Check Values (ICVs) (i.e., digital signatures or Message Authentication Codes (MACs)) as well as timestamps, using the generalized Mobile Ad Hoc Network (MANET) packet/message format defined in RFC 5444. It defines two Packet TLVs, two Message TLVs, and two Address Block TLVs for affixing ICVs and timestamps to a packet, a message, and an address, respectively.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc6622.
Copyright Notice
Copyright (c) 2012 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 (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.
Herberg & Clausen Standards Track [Page 1] RFC 6622 ICV and Timestamp TLVs for MANETs May 2012
Table of Contents
1. Introduction ....................................................3
2. Terminology .....................................................3
3. Applicability Statement .........................................3
4. Security Architecture ...........................................4
5. Overview and Functioning ........................................5
6. General ICV TLV Structure .......................................6
7. General Timestamp TLV Structure .................................6
8. Packet TLVs .....................................................7
8.1. Packet ICV TLV .............................................7
8.2. Packet TIMESTAMP TLV .......................................7
9. Message TLVs ....................................................8
9.1. Message ICV TLV ............................................8
9.2. Message TIMESTAMP TLV ......................................8
10. Address Block TLVs .............................................8
10.1. Address Block ICV TLV .....................................8
10.2. Address Block TIMESTAMP TLV ...............................9
11. ICV: Basic .....................................................9
12. ICV: Cryptographic Function over a Hash Value ..................9
12.1. General ICV TLV Structure ................................10
12.1.1. Rationale .........................................11
12.2. Considerations for Calculating the ICV ...................11
12.2.1. Packet ICV TLV ....................................11
12.2.2. Message ICV TLV ...................................11
12.2.3. Address Block ICV TLV .............................11
12.3. Example of a Message Including an ICV ....................12
13. IANA Considerations ...........................................13
13.1. Expert Review: Evaluation Guidelines .....................13
13.2. Packet TLV Type Registrations ............................14
13.3. Message TLV Type Registrations ...........................15
13.4. Address Block TLV Type Registrations .....................16
13.5. Hash Functions ...........................................17
13.6. Cryptographic Functions ..................................18
14. Security Considerations .......................................18
15. Acknowledgements ..............................................19
16. References ....................................................19
16.1. Normative References .....................................19
16.2. Informative References ...................................21
Herberg & Clausen Standards Track [Page 2] RFC 6622 ICV and Timestamp TLVs for MANETs May 2012
1. Introduction
This document specifies
o Two TLVs for carrying Integrity Check Values (ICVs) and timestamps
in packets, messages, and address blocks as defined by [RFC5444].
o A generic framework for ICVs, accounting (for Message TLVs) for
mutable message header fields (<msg-hop-limit> and
<msg-hop-count>), where these fields are present in messages.
This document sets up IANA registries for recording code points for hash-function and ICV calculation, respectively.
Moreover, in Section 12, this document defines the following:
o One common method for generating ICVs as a cryptographic function,
calculated over the hash value of the content.
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].
This document uses the terminology and notation defined in [RFC5444].
In particular, the following TLV fields from [RFC5444] are used in
this specification:
<msg-hop-limit> is the hop limit of a message, as specified in
Section 5.2 of [RFC5444].
<msg-hop-count> is the hop count of a message, as specified in
Section 5.2 of [RFC5444].
<length> is the length of a TLV in octets, as specified in
Section 5.4.1 of [RFC5444].
3. Applicability Statement
MANET routing protocols using the format defined in [RFC5444] are
accorded the ability to carry additional information in control
messages and packets, through the inclusion of TLVs. Information so
included MAY be used by a MANET routing protocol, or by an extension
of a MANET routing protocol, according to its specification.
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This document specifies how to include an ICV for a packet, a message, and addresses in address blocks within a message, by way of such TLVs. This document also specifies a) how to treat "mutable" fields, specifically the <msg-hop-count> and <msg-hop-limit> fields, if present in the message header when calculating ICVs, such that the resulting ICV can be correctly verified by any recipient, and b) how to include this ICV.
This document describes a generic framework for creating ICVs, and how to include these ICVs in TLVs. In Section 12, an example method for calculating such ICVs is given, using a cryptographic function over the hash value of the content.
4. Security Architecture
Basic MANET routing protocol specifications are often "oblivious to security"; however, they have a clause allowing a control message to be rejected as "badly formed" or "insecure" prior to the message being processed or forwarded. MANET routing protocols such as the Neighborhood Discovery Protocol (NHDP) [RFC6130] and the Optimized Link State Routing Protocol version 2 [OLSRv2] recognize external reasons (such as failure to verify an ICV) for rejecting a message that would be considered "invalid for processing". This architecture is a result of the observation that with respect to security in MANETs, "one size rarely fits all" and that MANET routing protocol deployment domains have varying security requirements ranging from "unbreakable" to "virtually none". The virtue of this approach is that MANET routing protocol specifications (and implementations) can remain "generic", with extensions providing proper security mechanisms specific to a deployment domain.
The MANET routing protocol "security architecture", in which this
specification situates itself, can therefore be summarized as
follows:
o Security-oblivious MANET routing protocol specifications, with a
clause allowing an extension to reject a message (prior to
processing/forwarding) as "badly formed" or "insecure".
o MANET routing protocol security extensions, rejecting messages as
"badly formed" or "insecure", as appropriate for a given security
requirement specific to a deployment domain.
o Code points and an exchange format for information, necessary for
specification of such MANET routing protocol security extensions.
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This document addresses the last of the issues listed above by specifying a common exchange format for cryptographic ICVs, making reservations from within the Packet TLV, Message TLV, and Address Block TLV registries of [RFC5444], to be used (and shared) among MANET routing protocol security extensions.
For the specific decomposition of an ICV into a cryptographic function over a hash value (specified in Section 12), this document establishes two IANA registries for code points for hash functions and cryptographic functions adhering to [RFC5444].
With respect to [RFC5444], this document is
o Intended to be used in the non-normative, but intended, mode of
use described in Appendix B of [RFC5444].
o A specific example of the Security Considerations section of
[RFC5444] (the authentication part).
5. Overview and Functioning
This document specifies a syntactical representation of security- related information for use with [RFC5444] addresses, messages, and packets, and also establishes IANA registrations of TLV types and type extension registries for these TLV types.
Moreover, this document provides guidelines for how MANET routing protocols and MANET routing protocol extensions using this specification should treat ICV and Timestamp TLVs, and mutable fields in messages. This specification does not represent a stand-alone protocol; MANET routing protocols and MANET routing protocol extensions, using this specification, MUST provide instructions as to how to handle packets, messages, and addresses with security information, associated as specified in this document.
This document assigns TLV types from the registries defined for Packet, Message, and Address Block TLVs in [RFC5444]. When a TLV type is assigned from one of these registries, a registry for type extensions for that TLV type is created by IANA. This document utilizes these type extension registries so created, in order to specify internal structure (and accompanying processing) of the <value> field of a TLV.
For example, and as defined in this document, an ICV TLV with type extension = 0 specifies that the <value> field has no pre-defined internal structure but is simply a sequence of octets. An ICV TLV with type extension = 1 specifies that the <value> field has a pre-defined internal structure and defines its interpretation.
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(Specifically, the <value> field consists of a cryptographic operation over a hash value, with fields indicating which hash function and cryptographic operation have been used; this is specified in Section 12.)
Other documents can request assignments for other type extensions; if they do so, they MUST specify their internal structure (if any) and interpretation.
6. General ICV TLV Structure
The value of the ICV TLV is
<value> := <ICV-value>
where
<ICV-value> is a field, of <length> octets, which contains the
information to be interpreted by the ICV verification process, as
specified by the type extension.
Note that this does not stipulate how to calculate the <ICV-value> nor the internal structure thereof, if any; such information MUST be specified by way of the type extension for the ICV TLV type. See Section 13. This document specifies two such type extensions -- one for ICVs without pre-defined structures, and one for ICVs constructed by way of a cryptographic operation over a hash value.
7. General Timestamp TLV Structure
The value of the Timestamp TLV is
<value> := <time-value>
where
<time-value> is an unsigned integer field, of length <length>, which
contains the timestamp.
Note that this does not stipulate how to calculate the
<time-value> nor the internal structure thereof, if any; such
information MUST be specified by way of the type extension for the
TIMESTAMP TLV type. See Section 13.
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A timestamp is essentially "freshness information". As such, its setting and interpretation are to be determined by the MANET routing protocol, or MANET routing protocol extension, that uses the timestamp and can, for example, correspond to a UNIX timestamp, GPS timestamp, or a simple sequence number.
8. Packet TLVs
Two Packet TLVs are defined: one for including the cryptographic ICV of a packet and one for including the timestamp indicating the time at which the cryptographic ICV was calculated.
8.1. Packet ICV TLV
A Packet ICV TLV is an example of an ICV TLV as described in Section 6.
The following considerations apply:
o Because packets as defined in [RFC5444] are never forwarded by
routers, no special considerations are required regarding mutable
fields (e.g., <msg-hop-count> and <msg-hop-limit>), if present,
when calculating the ICV.
o Any Packet ICV TLVs already present in the Packet TLV block MUST
be removed before calculating the ICV, and the Packet TLV block
size MUST be recalculated accordingly. Removed ICV TLVs MUST be
restored after having calculated the ICV value.
The rationale for removing any Packet ICV TLV already present prior to calculating the ICV is that several ICVs may be added to the same packet, e.g., using different ICV functions.
8.2. Packet TIMESTAMP TLV
A Packet TIMESTAMP TLV is an example of a Timestamp TLV as described in Section 7. If a packet contains a TIMESTAMP TLV and an ICV TLV, the TIMESTAMP TLV SHOULD be added to the packet before any ICV TLV, in order that it be included in the calculation of the ICV.
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9. Message TLVs
Two Message TLVs are defined: one for including the cryptographic ICV of a message and one for including the timestamp indicating the time at which the cryptographic ICV was calculated.
9.1. Message ICV TLV
A Message ICV TLV is an example of an ICV TLV as described in Section 6. When determining the <ICV-value> for a message, the following considerations MUST be applied:
o The fields <msg-hop-limit> and <msg-hop-count>, if present, MUST
both be assumed to have the value 0 (zero) when calculating
the ICV.
o Any Message ICV TLVs already present in the Message TLV block MUST
be removed before calculating the ICV, and the message size as
well as the Message TLV block size MUST be recalculated
accordingly. Removed ICV TLVs MUST be restored after having
calculated the ICV value.
The rationale for removing any Message ICV TLV already present prior to calculating the ICV is that several ICVs may be added to the same message, e.g., using different ICV functions.
9.2. Message TIMESTAMP TLV
A Message TIMESTAMP TLV is an example of a Timestamp TLV as described in Section 7. If a message contains a TIMESTAMP TLV and an ICV TLV, the TIMESTAMP TLV SHOULD be added to the message before the ICV TLV, in order that it be included in the calculation of the ICV.
10. Address Block TLVs
Two Address Block TLVs are defined: one for associating a cryptographic ICV to an address and one for including the timestamp indicating the time at which the cryptographic ICV was calculated.
10.1. Address Block ICV TLV
An Address Block ICV TLV is an example of an ICV TLV as described in Section 6. The ICV is calculated over the address, concatenated with any other values -- for example, any other Address Block TLV <value> fields -- associated with that address. A MANET routing protocol or MANET routing protocol extension using Address Block ICV TLVs MUST specify how to include any such concatenated attribute of the address
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in the verification process of the ICV. When determining the <ICV-value> for an address, the following consideration MUST be applied:
o If other TLV values are concatenated with the address for
calculating the ICV, these TLVs MUST NOT be Address Block ICV TLVs
already associated with the address.
The rationale for not concatenating the address with any ICV TLV values already associated with the address when calculating the ICV is that several ICVs may be added to the same address, e.g., using different ICV functions.
10.2. Address Block TIMESTAMP TLV
An Address Block TIMESTAMP TLV is an example of a Timestamp TLV as described in Section 7. If both a TIMESTAMP TLV and an ICV TLV are associated with an address, the TIMESTAMP TLV <value> MUST be covered when calculating the value of the ICV to be contained in the ICV TLV value (i.e., concatenated with the associated address and any other values as described in Section 10.1).
11. ICV: Basic
The basic ICV, represented by way of an ICV TLV with type
extension = 0, is a simple bit-field containing the cryptographic
ICV. This assumes that the mechanism stipulating how ICVs are
calculated and verified is established outside of this specification,
e.g., by way of administrative configuration or external out-of-band
signaling. Thus, the <ICV-value>, when using type extension = 0, is
<ICV-value> := <ICV-data>
where
<ICV-data> is an unsigned integer field, of length <length>, which
contains the cryptographic ICV.
12. ICV: Cryptographic Function over a Hash Value
One common way of calculating an ICV is applying a cryptographic function over a hash value of the content. This decomposition is specified in this section, using a type extension = 1 in the ICV TLVs.
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12.1. General ICV TLV Structure
The following data structure allows representation of a cryptographic
ICV, including specification of the appropriate hash function and
cryptographic function used for calculating the ICV:
<ICV-value> := <hash-function>
<cryptographic-function>
<key-id-length>
<key-id>
<ICV-data>
where
<hash-function> is an 8-bit unsigned integer field specifying the
hash function.
<cryptographic-function> is an 8-bit unsigned integer field
specifying the cryptographic function.
<key-id-length> is an 8-bit unsigned integer field specifying the
length of the <key-id> field in number of octets. The value 0x00
is reserved for using a pre-installed, shared key.
<key-id> is a field specifying the key identifier of the key that
was used to calculate the ICV of the message, which allows unique
identification of different keys with the same originator. It is
the responsibility of each key originator to make sure that
actively used keys that it issues have distinct key identifiers.
If <key-id-length> equals 0x00, the <key-id> field is not
contained in the TLV, and a pre-installed, shared key is used.
<ICV-data> is an unsigned integer field, whose length is
<length> - 3 - <key-id-length>, and which contains the
cryptographic ICV.
The version of this TLV, specified in this section, assumes that calculating the ICV can be decomposed into
ICV-value = cryptographic-function(hash-function(content))
The hash function and the cryptographic function correspond to the
entries in two IANA registries, which are set up by this
specification and are described in Section 13.
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12.1.1. Rationale
The rationale for separating the hash function and the cryptographic function into two octets instead of having all combinations in a single octet -- possibly as a TLV type extension -- is that adding further hash functions or cryptographic functions in the future may lead to a non-contiguous number space.
The rationale for not including a field that lists parameters of the cryptographic ICV in the TLV is that, before being able to validate a cryptographic ICV, routers have to exchange or acquire keys (e.g., public keys). Any additional parameters can be provided together with the keys in that bootstrap process. It is therefore not necessary, and would even entail an extra overhead, to transmit the parameters within every message. One implicitly available parameter is the length of the ICV, which is <length> - 3 - <key-id-length>, and which depends on the choice of the cryptographic function.
12.2. Considerations for Calculating the ICV
The considerations listed in the following subsections MUST be applied when calculating the ICV for Packet, Message, and Address ICV TLVs, respectively.
12.2.1. Packet ICV TLV
When determining the <ICV-value> for a packet, the ICV is calculated over the fields <hash-function>, <cryptographic-function>, <key-id-length>, and -- if present -- <key-id> (in that order), concatenated with the entire packet, including the packet header, all Packet TLVs (other than Packet ICV TLVs), and all included Messages and their message headers, in accordance with Section 8.1.
12.2.2. Message ICV TLV
When determining the <ICV-value> for a message, the ICV is calculated over the fields <hash-function>, <cryptographic-function>, <key-id-length>, and -- if present -- <key-id> (in that order), concatenated with the entire message. The considerations in Section 9.1 MUST be applied.
12.2.3. Address Block ICV TLV
When determining the <ICV-value> for an address, the ICV is calculated over the fields <hash-function>, <cryptographic-function>, <key-id-length>, and -- if present -- <key-id> (in that order), concatenated with the address, and concatenated with any other values -- for example, any other address block TLV <value> that is
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associated with that address. A MANET routing protocol or MANET routing protocol extension using Address Block ICV TLVs MUST specify how to include any such concatenated attribute of the address in the verification process of the ICV. The considerations in Section 10.1 MUST be applied.
12.3. Example of a Message Including an ICV
The sample message depicted in Figure 1 is derived from Appendix D of [RFC5444]. The message contains an ICV Message TLV, with the value representing an ICV that is 16 octets long of the whole message, and a key identifier that is 4 octets long. The type extension of the Message TLV is 1, for the specific decomposition of an ICV into a cryptographic function over a hash value, as specified in Section 12.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PV=0 | PF=8 | Packet Sequence Number | Message Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MF=15 | MAL=3 | Message Length = 44 | Msg. Orig Addr|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message Originator Address (cont) | Hop Limit |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Hop Count | Message Sequence Number | Msg. TLV Block|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length = 27 | ICV | MTLVF = 144 | MTLVExt = 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Value Len = 23 | Hash Func | Crypto Func |Key ID length=4|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Key Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ICV Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ICV Value (cont) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ICV Value (cont) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ICV Value (cont) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Example Message with ICV
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13. IANA Considerations
This specification defines the following:
o Two Packet TLV types, which have been allocated from the 0-223
range of the "Packet TLV Types" repository of [RFC5444], as
specified in Table 1.
o Two Message TLV types, which have been allocated from the 0-127
range of the "Message TLV Types" repository of [RFC5444], as
specified in Table 2.
o Two Address Block TLV types, which have been allocated from the
0-127 range of the "Address Block TLV Types" repository of
[RFC5444], as specified in Table 3.
This specification created the following:
o A type extension registry for each of these TLV types with initial
values as listed in Tables 1, 2, and 3.
IANA has assigned the same numerical value to the Packet TLV, Message TLV, and Address Block TLV types with the same name.
The following terms are used as defined in [BCP26]: "Namespace", "Registration", and "Designated Expert".
The following policy is used as defined in [BCP26]: "Expert Review".
13.1. Expert Review: Evaluation Guidelines
For TLV type extensions registries where an Expert Review is required, the Designated Expert SHOULD take the same general recommendations into consideration as those specified by [RFC5444].
For the Timestamp TLV, the same type extensions for all Packet, Message, and Address Block TLVs SHOULD be numbered identically.
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13.2. Packet TLV Type Registrations
IANA has made allocations from the "Packet TLV Types" namespace of [RFC5444] for the Packet TLVs specified in Table 1.
+-----------+------+-----------+------------------------------------+ | Name | Type | Type | Description | | | | Extension | | +-----------+------+-----------+------------------------------------+ | ICV | 5 | 0 | ICV of a packet | | | | | | | | | 1 | ICV, decomposed into cryptographic | | | | | function over a hash value, as | | | | | specified in Section 12 of this | | | | | document | | | | | | | | | 2-251 | Unassigned; Expert Review | | | | | | | | | 252-255 | Experimental Use | | | | | | | TIMESTAMP | 6 | 0 | Unsigned timestamp of arbitrary | | | | | length, given by the TLV Length | | | | | field. The MANET routing protocol | | | | | has to define how to interpret | | | | | this timestamp | | | | | | | | | 1 | Unsigned 32-bit timestamp, as | | | | | specified in [IEEE 1003.1-2008 | | | | | (POSIX)] | | | | | | | | | 2 | NTP timestamp format, as defined | | | | | in [RFC5905] | | | | | | | | | 3 | Signed timestamp of arbitrary | | | | | length with no constraints such as | | | | | monotonicity. In particular, it | | | | | may represent any random value | | | | | | | | | 4-251 | Unassigned; Expert Review | | | | | | | | | 252-255 | Experimental Use | +-----------+------+-----------+------------------------------------+
Table 1: Packet TLV Types
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13.3. Message TLV Type Registrations
IANA has made allocations from the "Message TLV Types" namespace of [RFC5444] for the Message TLVs specified in Table 2.
+-----------+------+-----------+------------------------------------+ | Name | Type | Type | Description | | | | Extension | | +-----------+------+-----------+------------------------------------+ | ICV | 5 | 0 | ICV of a message | | | | | | | | | 1 | ICV, decomposed into cryptographic | | | | | function over a hash value, as | | | | | specified in Section 12 of this | | | | | document | | | | | | | | | 2-251 | Unassigned; Expert Review | | | | | | | | | 252-255 | Experimental Use | | | | | | | TIMESTAMP | 6 | 0 | Unsigned timestamp of arbitrary | | | | | length, given by the TLV Length | | | | | field | | | | | | | | | 1 | Unsigned 32-bit timestamp, as | | | | | specified in [IEEE 1003.1-2008 | | | | | (POSIX)] | | | | | | | | | 2 | NTP timestamp format, as defined | | | | | in [RFC5905] | | | | | | | | | 3 | Signed timestamp of arbitrary | | | | | length with no constraints such as | | | | | monotonicity. In particular, it | | | | | may represent any random value | | | | | | | | | 4-251 | Unassigned; Expert Review | | | | | | | | | 252-255 | Experimental Use | +-----------+------+-----------+------------------------------------+
Table 2: Message TLV Types
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13.4. Address Block TLV Type Registrations
IANA has made allocations from the "Address Block TLV Types" namespace of [RFC5444] for the Packet TLVs specified in Table 3.
+-----------+------+-----------+------------------------------------+ | Name | Type | Type | Description | | | | Extension | | +-----------+------+-----------+------------------------------------+ | ICV | 5 | 0 | ICV of an object (e.g., an | | | | | address) | | | | | | | | | 1 | ICV, decomposed into cryptographic | | | | | function over a hash value, as | | | | | specified in Section 12 of this | | | | | document | | | | | | | | | 2-251 | Unassigned; Expert Review | | | | | | | | | 252-255 | Experimental Use | | | | | | | TIMESTAMP | 6 | 0 | Unsigned timestamp of arbitrary | | | | | length, given by the TLV Length | | | | | field | | | | | | | | | 1 | Unsigned 32-bit timestamp, as | | | | | specified in [IEEE 1003.1-2008 | | | | | (POSIX)] | | | | | | | | | 2 | NTP timestamp format, as defined | | | | | in [RFC5905] | | | | | | | | | 3 | Signed timestamp of arbitrary | | | | | length with no constraints such as | | | | | monotonicity. In particular, it | | | | | may represent any random value | | | | | | | | | 4-251 | Unassigned; Expert Review | | | | | | | | | 252-255 | Experimental Use | +-----------+------+-----------+------------------------------------+
Table 3: Address Block TLV Types
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13.5. Hash Functions
IANA has created a new registry for hash functions that can be used when creating an ICV, as specified in Section 12 of this document. The initial assignments and allocation policies are specified in Table 4.
+-------------+-----------+-----------------------------------------+ | Hash | Algorithm | Description | | Function | | | | Value | | | +-------------+-----------+-----------------------------------------+ | 0 | none | The "identity function": The hash value | | | | of an object is the object itself | | | | | | 1 | SHA1 | [NIST-FIPS-180-2] | | | | | | 2 | SHA224 | [NIST-FIPS-180-2-change] | | | | | | 3 | SHA256 | [NIST-FIPS-180-2] | | | | | | 4 | SHA384 | [NIST-FIPS-180-2] | | | | | | 5 | SHA512 | [NIST-FIPS-180-2] | | | | | | 6-251 | | Unassigned; Expert Review | | | | | | 252-255 | | Experimental Use | +-------------+-----------+-----------------------------------------+
Table 4: Hash-Function Registry
Herberg & Clausen Standards Track [Page 17] RFC 6622 ICV and Timestamp TLVs for MANETs May 2012
13.6. Cryptographic Functions
IANA has created a new registry for the cryptographic functions, as specified in Section 12 of this document. Initial assignments and allocation policies are specified in Table 5.
+----------------+-----------+--------------------------------------+ | Cryptographic | Algorithm | Description | | Function Value | | | +----------------+-----------+--------------------------------------+ | 0 | none | The "identity function": The value | | | | of an encrypted hash is the hash | | | | itself | | | | | | 1 | RSA | [RFC3447] | | | | | | 2 | DSA | [NIST-FIPS-186-3] | | | | | | 3 | HMAC | [RFC2104] | | | | | | 4 | 3DES | [NIST-SP-800-67] | | | | | | 5 | AES | [NIST-FIPS-197] | | | | | | 6 | ECDSA | [ANSI-X9-62-2005] | | | | | | 7-251 | | Unassigned; Expert Review | | | | | | 252-255 | | Experimental Use | +----------------+-----------+--------------------------------------+
Table 5: Cryptographic Function Registry
14. Security Considerations
This document does not specify a protocol. It provides a syntactical component for cryptographic ICVs of messages and packets, as defined in [RFC5444]. It can be used to address security issues of a MANET routing protocol or MANET routing protocol extension. As such, it has the same security considerations as [RFC5444].
In addition, a MANET routing protocol or MANET routing protocol
extension that uses this specification MUST specify how to use the
framework, and the TLVs presented in this document. In addition, the
protection that the MANET routing protocol or MANET routing protocol
extensions attain by using this framework MUST be described.
Herberg & Clausen Standards Track [Page 18] RFC 6622 ICV and Timestamp TLVs for MANETs May 2012
As an example, a MANET routing protocol that uses this component to reject "badly formed" or "insecure" messages if a control message does not contain a valid ICV SHOULD indicate the security assumption that if the ICV is valid, the message is considered valid. It also SHOULD indicate the security issues that are counteracted by this measure (e.g., link or identity spoofing) as well as the issues that are not counteracted (e.g., compromised keys).
15. Acknowledgements
The authors would like to thank Bo Berry (Cisco), Alan Cullen (BAE), Justin Dean (NRL), Christopher Dearlove (BAE), Paul Lambert (Marvell), Jerome Milan (Ecole Polytechnique), and Henning Rogge (FGAN) for their constructive comments on the document.
The authors also appreciate the detailed reviews from the Area Directors, in particular Stewart Bryant (Cisco), Stephen Farrell (Trinity College Dublin), and Robert Sparks (Tekelec), as well as Donald Eastlake (Huawei) from the Security Directorate.
16. References
16.1. Normative References
[ANSI-X9-62-2005]
American National Standards Institute, "Public Key
Cryptography for the Financial Services Industry: The
Elliptic Curve Digital Signature Algorithm (ECDSA)",
ANSI X9.62-2005, November 2005.
[BCP26] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008.
[IEEE 1003.1-2008 (POSIX)]
IEEE Computer Society, "1003.1-2008 Standard for
Information Technology-Portable Operating System
Interface (POSIX) Base Specifications, Issue 7",
December 2008.
[NIST-FIPS-180-2]
National Institute of Standards and Technology,
"Specifications for the Secure Hash Standard",
FIPS 180-2, August 2002.
Herberg & Clausen Standards Track [Page 19] RFC 6622 ICV and Timestamp TLVs for MANETs May 2012
[NIST-FIPS-180-2-change]
National Institute of Standards and Technology, "Federal
Information Processing Standards Publication 180-2
(+ Change Notice to include SHA-224)", FIPS 180-2,
August 2002, <http:// csrc.nist.gov/publications/fips/
fips180-2/fips180-2withchangenotice.pdf>.
[NIST-FIPS-186-3]
National Institute of Standards and Technology, "Digital
Signature Standard (DSS)", FIPS 186-3, June 2009.
[NIST-FIPS-197]
National Institute of Standards and Technology,
"Specification for the Advanced Encryption Standard
(AES)", FIPS 197, November 2001.
[NIST-SP-800-67]
National Institute of Standards and Technology,
"Recommendation for the Triple Data Encryption Algorithm
(TDEA) Block Cipher", Special Publication 800-67,
May 2004.
[RFC2104] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC:
Keyed-Hashing for Message Authentication", RFC 2104,
February 1997.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3447] Jonsson, J. and B. Kaliski, "Public-Key Cryptography
Standards (PKCS) #1: RSA Cryptography Specifications
Version 2.1", RFC 3447, February 2003.
[RFC5444] Clausen, T., Dearlove, C., Dean, J., and C. Adjih,
"Generalized Mobile Ad Hoc Network (MANET) Packet/Message
Format", RFC 5444, February 2009.
[RFC5905] Mills, D., Martin, J., Ed., Burbank, J., and W. Kasch,
"Network Time Protocol Version 4: Protocol and Algorithms
Specification", RFC 5905, June 2010.
Herberg & Clausen Standards Track [Page 20] RFC 6622 ICV and Timestamp TLVs for MANETs May 2012
16.2. Informative References
[OLSRv2] Clausen, T., Dearlove, C., Jacquet, P., and U. Herberg,
"The Optimized Link State Routing Protocol version 2",
Work in Progress, March 2012.
[RFC6130] Clausen, T., Dearlove, C., and J. Dean, "Mobile Ad Hoc
Network (MANET) Neighborhood Discovery Protocol (NHDP)",
RFC 6130, April 2011.
Authors' Addresses
Ulrich Herberg Fujitsu Laboratories of America 1240 E. Arques Ave. Sunnyvale, CA 94085 USA
EMail: ulrich@herberg.name URI: http://www.herberg.name/
Thomas Heide Clausen LIX, Ecole Polytechnique 91128 Palaiseau Cedex France
Phone: +33 6 6058 9349 EMail: T.Clausen@computer.org URI: http://www.thomasclausen.org/
Herberg & Clausen Standards Track [Page 21]
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