Mobile Ad hoc Networking (MANET) U. Herberg
Internet-Draft T. Clausen
Intended status: Standards Track LIX, Ecole Polytechnique
Expires: January 28, 2011 July 27, 2010
MANET Cryptographical Signature TLV Definition
draft-ietf-manet-packetbb-sec-01
Abstract
This document describes general and flexible TLVs (type-length-value
structure) for representing cryptographic signatures as well as
timestamps, using the generalized MANET packet/message format
[RFC5444]. It defines two Packet TLVs, two Message TLVs, and two
Address Block TLVs, for affixing cryptographic signatures and
timestamps to a packet, message and address, respectively.
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 January 28, 2011.
Copyright Notice
Copyright (c) 2010 IETF Trust and the persons identified as the
document authors. All rights reserved.
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the Trust Legal Provisions and are provided without warranty as
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Applicability Statement . . . . . . . . . . . . . . . . . . . 3
4. Security Architecture . . . . . . . . . . . . . . . . . . . . 4
5. Protocol Overview and Functioning . . . . . . . . . . . . . . 5
6. Imported TLV Fields . . . . . . . . . . . . . . . . . . . . . 5
7. General Signature TLV Structure . . . . . . . . . . . . . . . 5
7.1. Rationale . . . . . . . . . . . . . . . . . . . . . . . . 6
8. General Timestamp TLV Structure . . . . . . . . . . . . . . . 6
9. Packet TLVs . . . . . . . . . . . . . . . . . . . . . . . . . 7
9.1. Packet SIGNATURE TLV . . . . . . . . . . . . . . . . . . . 7
9.2. Packet TIMESTAMP TLV . . . . . . . . . . . . . . . . . . . 8
10. Message TLVs . . . . . . . . . . . . . . . . . . . . . . . . . 8
10.1. Message SIGNATURE TLV . . . . . . . . . . . . . . . . . . 8
10.2. Message TIMESTAMP TLV . . . . . . . . . . . . . . . . . . 8
11. Address Block TLVs . . . . . . . . . . . . . . . . . . . . . . 9
11.1. Address Block SIGNATURE TLV . . . . . . . . . . . . . . . 9
11.2. Address Block TIMESTAMP TLV . . . . . . . . . . . . . . . 9
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
12.1. TLV Registrations . . . . . . . . . . . . . . . . . . . . 9
12.1.1. Expert Review: Evaluation Guidelines . . . . . . . . 10
12.1.2. Packet TLV Type Registrations . . . . . . . . . . . . 10
12.1.3. Message TLV Type Registrations . . . . . . . . . . . 10
12.1.4. Address Block TLV Type Registrations . . . . . . . . 11
12.2. New IANA Registries . . . . . . . . . . . . . . . . . . . 11
12.2.1. Expert Review: Evaluation Guidelines . . . . . . . . 12
12.2.2. Hash Function . . . . . . . . . . . . . . . . . . . . 12
12.2.3. Cryptographic Algorithm . . . . . . . . . . . . . . . 12
13. Security Considerations . . . . . . . . . . . . . . . . . . . 13
14. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 13
15. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
15.1. Normative References . . . . . . . . . . . . . . . . . . . 13
15.2. Informative References . . . . . . . . . . . . . . . . . . 14
Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 14
A.1. Example of a Signed Message . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16
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1. Introduction
This document specifies:
o two TLVs for carrying cryptographic signatures and timestamps in
packets, messages and address blocks as defined by [RFC5444],
o how cryptographic signatures are calculated, taking (for Message
TLVs) into account the mutable message header fields (<msg-hop-
limit> and <msg-hop-count>) where these fields are present in
messages.
This document requests from IANA:
o allocations for these Packet, Message, and Address Block TLVs from
the 0-223 Packet TLV range, the 0-127 Message TLV range and the
0-127 Address Block TLV range from [RFC5444],
o creation of two IANA registries for recording code points for hash
function and signature calculation, respectively.
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].
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 inclusion of TLVs. Information so
included MAY be used by a routing protocol, or by an extension of a
routing protocol, according to its specification.
This document specifies how to include a cryptographic signature for
a packet, message or address by way of such TLVs. This document also
specifies how to treat "mutable" fields (<msg-hop-count> and <msg-
hop-limit>), if present, in the message header when calculating
signatures, such that the resulting signature can be correctly
verified by any recipient, and how to include this signature.
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4. Security Architecture
Basic MANET routing protocol specifications are often "oblivious to
security", however have a clause allowing a control message to be
rejected as "badly formed" prior to it being processed or forwarded.
Protocols such as [NHDP] and [OLSRv2] recognize external reasons
(such as failure to verify a signature) for rejecting a message as
"badly formed", and therefore "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 deployment-domain specific security mechanisms.
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".
o MANET routing protocol security extensions, rejecting messages as
"badly formed", as appropriate for a given deployment-domain
specific security requirement.
o Code-points and an exchange format for information, necessary for
specification of such MANET routing protocol security extensions.
This document addresses the last of these issues, by specifying a
common exchange format for cryptographic signatures, 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, establishing two IANA
registries for code-points for hash functions and cryptographic
functions adhering to [RFC5444].
With respect to [RFC5444], this document:
o is intended to be used in the non-normative, but intended, mode of
use of [RFC5444] as described in its Appendix B.
o is a specific example of the Security Considerations section of
[RFC5444] (the authentication part).
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5. Protocol Overview and Functioning
This specification does not describe a protocol, nor does it mandate
specific router or protocol behavior. It represents a purely
syntactical representation of security related information for use
with [RFC5444] addresses, messages and packets, as well as
establishes IANA registrations and registries.
6. Imported TLV Fields
In this specification, the following TLV fields from [RFC5444] are
used:
<msg-hop-limit> - hop limit of a message, as specified in Section
5.2 of [RFC5444].
<msg-hop-count> - hop count of a message, as specified in Section
5.2 of [RFC5444].
<length> - length of a TLV in octets, as specified in Section 5.4.1
of [RFC5444].
7. General Signature TLV Structure
The following data structure allows representation of a cryptographic
signature, including specification of the appropriate hash function
and cryptographic function used for calculating the signature. This
<signature> data structure is specified, using the regular expression
syntax of [RFC5444], as:
<signature> := <hash-function>
<cryptographic-function>
<key-index>
<signature-value>
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.
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<key-index> is an 8-bit unsigned integer field specifying the key
index of the key which was used to sign 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 indices and
that all key indices have a value unequal to 0x00. Value 0x00 is
reserved for a pre-installed, shared key.
<signature-value> is an unsigned integer field, whose length is
<length>-2, and which contains the cryptographic signature.
The basic version of this TLV assumes that calculating the signature
can be decomposed into:
signature-value = cryptographic-function(hash-function(content))
The hash function and the cryptographic function correspond to the
entries in two IANA registries, set up by this specification in
Section 12.
7.1. 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 TLV type extension - is twofold: First, if
further hash functions or cryptographic functions are added in the
future, the number space might not remain continuous. More
importantly, the number space of possible combinations would be
rapidly exhausted. As new or improved cryptographic mechanism are
continuously being developed and introduced, this format should be
able to accommodate such for the foreseeable future.
The rationale for not including a field that lists parameters of the
cryptographic signature in the TLV is, that before being able to
validate a cryptographic signature, 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 inherently
included parameter is the length of the signature, which is <length>
- 2 and which depends on the choice of the cryptographic function.
8. General Timestamp TLV Structure
The following data structure allows the representation of a
timestamp. This <timestamp> data structure is specified as:
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<timestamp> := <time-value>
where:
<time-value> is an unsigned integer field, whose length is <length>,
and which contains the timestamp. The value of this variable is
to be interpreted by the routing protocol as specified by the type
extension of the Timestamp TLV, see Section 12.
A timestamp is essentially "freshness information". As such, its
setting and interpretation is to be determined by the routing
protocol (or the extension to a routing protocol) that uses it, and
may e.g. correspond to a UNIX-timestamp, GPS timestamp or a simple
sequence number.
9. Packet TLVs
Two Packet TLVs are defined, for including the cryptographic
signature of a packet, and for including the timestamp indicating the
time at which the cryptographic signature was calculated.
9.1. Packet SIGNATURE TLV
A Packet SIGNATURE TLV is an example of a Signature TLV as described
in Section 7. When calculating the <signature-value> for a Packet,
the signature is calculated over the three fields <hash-function>,
<cryptographic-function> and <key-index> (in that order),
concatenated with the entire Packet, including the packet header, all
Packet TLVs (other than Packet SIGNATURE TLVs) and all included
Messages and their message headers.
The following considerations apply:
o As packets defined in [RFC5444] are never forwarded by routers, it
is unnecessary to consider mutable fields (e.g. <msg-hop-count>
and <msg-hop-limit>), if present, when calculating the signature.
o any Packet SIGNATURE TLVs already present in the Packet TLV block
MUST be removed before calculating the signature, and the Packet
TLV block size MUST be recalculated accordingly. The TLVs can be
restored after having calculated the signature value.
The rationale for removing any Packet SIGNATURE TLV already present
prior to calculating the signature, is that several signatures may be
added to the same packet, e.g., using different signature functions.
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9.2. Packet TIMESTAMP TLV
A Packet TIMESTAMP TLV is an example of a Timestamp TLV as described
in Section 8. If a packet contains a TIMESTAMP TLV and a SIGNATURE
TLV, the TIMESTAMP TLV SHOULD be added to the packet before any
SIGNATURE TLV, in order that it be included in the calculation of the
signature.
10. Message TLVs
Two Message TLVs are defined, for including the cryptographic
signature of a message, and for including the timestamp indicating
the time at which the cryptographic signature was calculated.
10.1. Message SIGNATURE TLV
A Message SIGNATURE TLV is an example of a Signature TLV as described
in Section 7. When determining the <signature-value> for a message,
the signature is calculated over the three fields <hash-function>,
<cryptographic-function>, and <key-index> (in that order),
concatenated with the entire message with the following
considerations:
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
signature.
o any Message SIGNATURE TLVs already present in the Message TLV
block MUST be removed before calculating the signature, and the
message size as well as the Message TLV block size MUST be
recalculated accordingly. The TLVs can be restored after having
calculated the signature value.
The rationale for removing any Message SIGNATURE TLV already present
prior to calculating the signature, is that several signatures may be
added to the same message, e.g., using different signature functions.
10.2. Message TIMESTAMP TLV
A Message TIMESTAMP TLV is an example of a Timestamp TLV as described
in Section 8. If a message contains a TIMESTAMP TLV and a SIGNATURE
TLV, the TIMESTAMP TLV SHOULD be added to the message before the
SIGNATURE TLV, in order that it be included in the calculation of the
signature.
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11. Address Block TLVs
Two Address Block TLVs are defined, for associating a cryptographic
signature to an address, and for including the timestamp indicating
the time at which the cryptographic signature was calculated.
11.1. Address Block SIGNATURE TLV
An Address Block SIGNATURE TLV is an example of a Signature TLV as
described in Section 7. The signature is calculated over the three
fields <hash-function>, <cryptographic-function>, and <key-index> (in
that order), concatenated with the address, concatenated with any
other values, for example, any other TLV value that is associated
with that address. A routing protocol or routing protocol extension
using Address Block SIGNATURE TLVs MUST specify how to include any
such concatenated attribute of the address in the verification
process of the signature.
11.2. Address Block TIMESTAMP TLV
An Address Block TIMESTAMP TLV is an example of a Timestamp TLV as
described in Section 8. If both a TIMESTAMP TLV and a SIGNATURE TLV
are associated with an address, the timestamp value should be
considered when calculating the value of the signature.
12. IANA Considerations
This section specifies requests to IANA.
12.1. TLV Registrations
This specification defines:
o two Packet TLV types which must be allocated from the 0-223 range
of the "Assigned Packet TLV Types" repository of [RFC5444] as
specified in Table 1,
o two Message TLV types which must be allocated from the 0-127 range
of the "Assigned Message TLV Types" repository of [RFC5444] as
specified in Table 2,
o and two Address Block TLV types which must be allocated from the
0-127 range of the "Assigned Address Block TLV Types" repository
of [RFC5444] as specified in Table 3.
This specification requests:
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o set up of type extension registries for these TLV types.
IANA is requested to assign the same numerical value to the Packet
TLV, Message TLV and Address Block TLV types with the same name.
12.1.1. Expert Review: Evaluation Guidelines
For the registries for TLV type extensions where an Expert Review is
required, the designated expert SHOULD take the same general
recommendations into consideration as are specified by [RFC5444].
For the Timestamp TLV, the same type extensions for all Packet,
Message and Address TLVs should be numbered identically.
12.1.2. Packet TLV Type Registrations
The Packet TLVs as specified in Table 1 must be allocated from the
"Packet TLV Types" namespace of [RFC5444].
+-----------+------+-----------+------------------------------------+
| Name | Type | Type | Description |
| | | Extension | |
+-----------+------+-----------+------------------------------------+
| SIGNATURE | TBD3 | 0 | Signature of a packet |
| | | 1-223 | Expert Review |
| | | 224-255 | Experimental Use |
| TIMESTAMP | TBD4 | 0 | Unsigned timestamp of arbitrary |
| | | | length, given by the TLV length |
| | | | field. The MANET routing protocol |
| | | | has to define how to interpret |
| | | | this timestamp |
| | | 1-223 | Expert Review |
| | | 224-255 | Experimental Use |
+-----------+------+-----------+------------------------------------+
Table 1: Packet TLV types
12.1.3. Message TLV Type Registrations
The Message TLVs as specified in Table 2 must be allocated from the
"Message TLV Types" namespace of [RFC5444].
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+-----------+------+-----------+------------------------------------+
| Name | Type | Type | Description |
| | | Extension | |
+-----------+------+-----------+------------------------------------+
| SIGNATURE | TBD1 | 0 | Signature of a message |
| | | 1-223 | Expert Review |
| | | 224-255 | Experimental Use |
| TIMESTAMP | TBD2 | 0 | Unsigned timestamp of arbitrary |
| | | | length, given by the TLV length |
| | | | field. |
| | | 1-223 | Expert Review |
| | | 224-255 | Experimental Use |
+-----------+------+-----------+------------------------------------+
Table 2: Message TLV types
12.1.4. Address Block TLV Type Registrations
The Address Block TLVs as specified in Table 3 must be allocated from
the "Address Block TLV Types" namespace of [RFC5444].
+-----------+------+-----------+------------------------------------+
| Name | Type | Type | Description |
| | | Extension | |
+-----------+------+-----------+------------------------------------+
| SIGNATURE | TBD1 | 0 | Signature of an object (e.g. an |
| | | | address) |
| | | 1-223 | Expert Review |
| | | 224-255 | Experimental Use |
| TIMESTAMP | TBD2 | 0 | Unsigned timestamp of arbitrary |
| | | | length, given by the TLV length |
| | | | field. |
| | | 1-223 | Expert Review |
| | | 224-255 | Experimental Use |
+-----------+------+-----------+------------------------------------+
Table 3: Address Block TLV types
12.2. New IANA Registries
This document introduces three namespaces that have been registered:
Packet TLV Types, Message TLV Types, and Address Block TLV Types.
This section specifies IANA registries for these namespaces and
provides guidance to the Internet Assigned Numbers Authority
regarding registrations in these namespaces.
The following terms are used with the meanings defined in [BCP26]:
"Namespace", "Assigned Value", "Registration", "Unassigned",
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"Reserved", "Hierarchical Allocation", and "Designated Expert".
The following policies are used with the meanings defined in [BCP26]:
"Private Use", "Expert Review", and "Standards Action".
12.2.1. Expert Review: Evaluation Guidelines
For the registries for the following tables where an Expert Review is
required, the designated expert SHOULD take the same general
recommendations into consideration as are specified by [RFC5444].
12.2.2. Hash Function
IANA is requested to create a new registry for the hash functions
that can be used when creating a signature. 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 |
| 1-223 | | Expert Review |
| 224-255 | | Experimental Use |
+-------------+-----------+-----------------------------------------+
Table 4: Hash-Function registry
12.2.3. Cryptographic Algorithm
IANA is requested to create a new registry for the cryptographic
function. 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 |
| 1-223 | | Expert Review |
| 224-255 | | Experimental Use |
+----------------+-----------+--------------------------------------+
Table 5: Cryptographic function registry
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13. Security Considerations
This document does not specify a protocol itself. However, it
provides a syntactical component for cryptographic signatures of
messages and packets as defined in [RFC5444]. It can be used to
address security issues of a protocol or extension that uses the
component specified in this document. As such, it has the same
security considerations as [RFC5444].
In addition, a protocol that includes this component MUST specify the
usage as well as the security that is attained by the cryptographic
signatures of a message or a packet.
As an example, a routing protocol that uses this component to reject
"badly formed" messages if a control message does not contain a valid
signature, should indicate the security assumption that if the
signature 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).
14. Acknowledgements
The authors would like to thank Jerome Milan (Ecole Polytechnique)
for his advice as cryptographer. In addition, many thanks to Bo
Berry (Cisco), Alan Cullen (BAE), Justin Dean (NRL), Christopher
Dearlove (BAE), Paul Lambert (Marvell), and Henning Rogge (FGAN) for
their constructive comments on the document.
15. References
15.1. Normative References
[BCP26] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", RFC 5226, BCP 26,
May 2008.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, BCP 14, March 1997.
[RFC5444] Clausen, T., Dearlove, C., Dean, J., and C. Adjih,
"Generalized MANET Packet/Message Format", RFC 5444,
February 2009.
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15.2. Informative References
[NHDP] Clausen, T., Dean, J., and C. Dearlove, "MANET
Neighborhood Discovery Protocol (NHDP)", work in
progress draft-ietf-manet-nhdp-14.txt, July 2010.
[OLSRv2] Clausen, T., Dearlove, C., and P. Jacquet, "The Optimized
Link State Routing Protocol version 2", work in
progress draft-ietf-manet-olsrv2-11.txt, April 2010.
Appendix A. Examples
A.1. Example of a Signed Message
The sample message depicted in Figure 1 is derived from the appendix
of [RFC5444]. A SIGNATURE Message TLV has been added, with the value
representing a 15 octet long signature of the whole message.
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 1 0 0 0| Packet Sequence Number | Message Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|1 1 1 1 0 0 1 1|0 0 0 0 0 0 0 0 0 1 0 0 1 1 0 0| Orig Addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Originator Address (cont) | Hop Limit |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Hop Count | Message Sequence Number |0 0 0 0 0 0 0 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 1 1 1 1 0| SIGNATURE |0 0 0 1 0 0 0 0|0 0 0 1 0 0 1 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Hash Func | Crypto Func | Key Index | Sign. Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Signature Value (cont) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Signature Value (cont) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Signature Value (cont) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Signature Value (cont) | TLV Type |0 0 0 1 0 0 0 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 1 1 0| Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value (cont) |0 0 0 0 0 0 1 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 1 1 0 0 0 0|0 0 0 0 0 0 1 0| Mid |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mid | Prefix Length |0 0 0 0 0 0 0 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 0 0|0 0 0 0 0 0 1 1|1 0 0 0 0 0 0 0|0 0 0 0 0 0 1 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Head | Mid |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mid | Mid |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1| TLV Type |0 0 0 1 0 0 0 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 1 0| Value | TLV Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 1 0 0 0 0 0| Index Start | Index Stop |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Example message with signature
Herberg & Clausen Expires January 28, 2011 [Page 15]
Internet-Draft MANET Cryptographical Signature TLV July 2010
Authors' Addresses
Ulrich Herberg
LIX, Ecole Polytechnique
91128 Palaiseau Cedex,
France
Phone: +33-1-6933-4126
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 Expires January 28, 2011 [Page 16]
