Mobile Ad hoc Networking (MANET) U. Herberg Internet-Draft Fujitsu Laboratories of America Intended status: Standards Track T. Clausen Expires: August 3, 2012 LIX, Ecole Polytechnique January 31, 2012 MANET Cryptographical Signature TLV Definition draft-ietf-manet-packetbb-sec-08 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 defined in RFC 5444. 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 Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on August 3, 2012. 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 Herberg & Clausen Expires August 3, 2012 [Page 1] Internet-Draft MANET Cryptographical Signature TLV January 2012 the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Applicability Statement . . . . . . . . . . . . . . . . . . . 4 4. Security Architecture . . . . . . . . . . . . . . . . . . . . 4 5. Overview and Functioning . . . . . . . . . . . . . . . . . . . 5 6. General Signature TLV Structure . . . . . . . . . . . . . . . 6 7. General Timestamp TLV Structure . . . . . . . . . . . . . . . 6 8. Packet TLVs . . . . . . . . . . . . . . . . . . . . . . . . . 7 8.1. Packet SIGNATURE TLV . . . . . . . . . . . . . . . . . . . 7 8.2. Packet TIMESTAMP TLV . . . . . . . . . . . . . . . . . . . 7 9. Message TLVs . . . . . . . . . . . . . . . . . . . . . . . . . 8 9.1. Message SIGNATURE TLV . . . . . . . . . . . . . . . . . . 8 9.2. Message TIMESTAMP TLV . . . . . . . . . . . . . . . . . . 8 10. Address Block TLVs . . . . . . . . . . . . . . . . . . . . . . 8 10.1. Address Block SIGNATURE TLV . . . . . . . . . . . . . . . 9 10.2. Address Block TIMESTAMP TLV . . . . . . . . . . . . . . . 9 11. Signature: Basic . . . . . . . . . . . . . . . . . . . . . . . 9 12. Signature: Cryptographic Function over a Hash Value . . . . . 10 12.1. General Signature TLV Structure . . . . . . . . . . . . . 10 12.1.1. Rationale . . . . . . . . . . . . . . . . . . . . . . 11 12.2. Considerations for Calculating the Signature . . . . . . . 11 12.2.1. Packet SIGNATURE TLV . . . . . . . . . . . . . . . . 11 12.2.2. Message SIGNATURE TLV . . . . . . . . . . . . . . . . 11 12.2.3. Address Block SIGNATURE TLV . . . . . . . . . . . . . 11 12.3. Example of a Signed Message . . . . . . . . . . . . . . . 12 13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 13.1. Expert Review: Evaluation Guidelines . . . . . . . . . . . 13 13.2. Packet TLV Type Registrations . . . . . . . . . . . . . . 13 13.3. Message TLV Type Registrations . . . . . . . . . . . . . . 14 13.4. Address Block TLV Type Registrations . . . . . . . . . . . 15 13.5. Hash Function . . . . . . . . . . . . . . . . . . . . . . 15 13.6. Cryptographic Algorithm . . . . . . . . . . . . . . . . . 16 14. Security Considerations . . . . . . . . . . . . . . . . . . . 16 15. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 16 16. References . . . . . . . . . . . . . . . . . . . . . . . . . . 17 16.1. Normative References . . . . . . . . . . . . . . . . . . . 17 16.2. Informative References . . . . . . . . . . . . . . . . . . 17 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 17 Herberg & Clausen Expires August 3, 2012 [Page 2] Internet-Draft MANET Cryptographical Signature TLV January 2012 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 A generic framework for calculating cryptographic signatures, accounting (for Message TLVs) for mutable message header fields ( and ), 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. Finally, this document defines, in Section 12: o One common method for generating signatures as a cryptographic function, calculated over the hash value of the content to be signed. 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: - hop limit of a message, as specified in Section 5.2 of [RFC5444]. - hop count of a message, as specified in Section 5.2 of [RFC5444]. Herberg & Clausen Expires August 3, 2012 [Page 3] Internet-Draft MANET Cryptographical Signature TLV January 2012 - 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 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. This document specifies how to include a cryptographic signature for a packet, a message, and addresses in address blocks within a message, by way of such TLVs. This document also specifies how to treat "mutable" fields, specifically the and fields, 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. This document describes a generic framework for creating signatures, and how to include these signatures in TLVs. In Section 12, an example method for calculating such signatures is given, using a cryptographic function over the hash value of the content to be signed. 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. MANET routing protocols such as [RFC6130] 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: Herberg & Clausen Expires August 3, 2012 [Page 4] Internet-Draft MANET Cryptographical Signature TLV January 2012 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. For the specific decomposition of a signature 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: o Is intended to be used in the non-normative, but intended, mode of use described in Appendix B of [RFC5444]. o Is 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, as well as establishes IANA registrations and registries. Moreover, this document provides guidelines for how MANET routing protocols, and MANET routing protocol extensions, using this specification, should treat Signature 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 requests assignment of TLV types from the registries defined for Packet, Message and Address Block TLVs in [RFC5444]. Herberg & Clausen Expires August 3, 2012 [Page 5] Internet-Draft MANET Cryptographical Signature TLV January 2012 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 field of a TLV. For example, and as defined in this document, a SIGNATURE TLV with Type Extension = 0 specifies that the field has no pre- defined internal structure, but is simply a sequence of octets. A SIGNATURE TLV with Type Extension = 1 specifies that the field has a pre-defined internal structure, and defines its interpretation (specifically, the field consists of a cryptographic operation over a hash value, with fields indicating which hash function and cryptographic operation has been used, specified in Section 12). Other documents can request assignments for other Type Extensions, and MUST, if so, specify their internal structure (if any) and interpretation. 6. General Signature TLV Structure The value of the Signature TLV is: := where: is a field, of octets, which contains the information, to be interpreted by the signature verification process, as specified by the Type Extension. Note that this does not stipulate how to calculate the , nor the internal structure hereof, if any; such MUST be specified by way of the Type Extension for the SIGNATURE TLV type, see Section 13. This document specifies two such type-extensions, for signatures without pre-defined structures, and for signatures constructed by way of a cryptographic operation over a hash-value. 7. General Timestamp TLV Structure The value of the Timestamp TLV is: := where: Herberg & Clausen Expires August 3, 2012 [Page 6] Internet-Draft MANET Cryptographical Signature TLV January 2012 is an unsigned integer field, of length , which contains the timestamp. Note that this does not stipulate how to calculate the , nor the internal structure hereof, if any; such MUST be specified by way of the Type Extension for the TIMESTAMP TLV type, see Section 13. A timestamp is essentially "freshness information". As such, its setting and interpretation is to be determined by the MANET routing protocol, or MANET routing protocol extension, that uses the timestamp, and can, e.g., correspond to a UNIX-timestamp, GPS timestamp or a simple sequence number. 8. 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. 8.1. Packet SIGNATURE TLV A Packet SIGNATURE TLV is an example of a Signature TLV as described in Section 6. The following considerations apply: o As packets defined in [RFC5444] are never forwarded by routers, no special considerations are required regarding mutable fields (e.g. and ), 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. Removed SIGNATURE TLVs SHOULD 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. 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 a SIGNATURE TLV, the TIMESTAMP TLV SHOULD be added to the packet before any Herberg & Clausen Expires August 3, 2012 [Page 7] Internet-Draft MANET Cryptographical Signature TLV January 2012 SIGNATURE TLV, in order that it be included in the calculation of the signature. 9. 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. 9.1. Message SIGNATURE TLV A Message SIGNATURE TLV is an example of a Signature TLV as described in Section 6. When determining the for a message, the following considerations MUST be applied: o The fields and , 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. Removed SIGNATURE TLVs SHOULD 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. 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 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. 10. 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. Herberg & Clausen Expires August 3, 2012 [Page 8] Internet-Draft MANET Cryptographical Signature TLV January 2012 10.1. Address Block SIGNATURE TLV An Address Block SIGNATURE TLV is an example of a Signature TLV as described in Section 6. The signature is calculated over the address, concatenated with any other values, for example, any other address block TLV fields, that is associated with that address. A MANET routing protocol or MANET 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. When determining the for an address, the following consideration MUST be applied: o If other TLV values are concatenated with the address for calculating the signature, these TLVs MUST NOT be Address Block SIGNATURE TLVs already associated with the address. The rationale for not concatenating the address with any SIGNATURE TLV values already associated with the address when calculating the signature is that several signatures may be added to the same address, e.g., using different signature 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 a SIGNATURE TLV are associated with an address, the TIMESTAMP TLV SHOULD be considered when calculating the value of the signature. 11. Signature: Basic The basic signature, represented by way of a SIGNATURE TLV with Type Extension = 0, is a simple bit-field containing the cryptographic signature. This assumes that the mechanism stipulating how signatures 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 for when using Type Extension = 0 is: := where: is an unsigned integer field, of length , which contains the cryptographic signature. Herberg & Clausen Expires August 3, 2012 [Page 9] Internet-Draft MANET Cryptographical Signature TLV January 2012 12. Signature: Cryptographic Function over a Hash Value One common way of calculating a signature is applying a cryptographic function on a hash value of the content. This decomposition is specified in the following, using a Type Extension = 1 in the Signature TLVs. 12.1. 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: := where: is an 8-bit unsigned integer field specifying the hash function. is an 8-bit unsigned integer field specifying the cryptographic function. 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 not equal to 0x00. The value 0x00 is reserved for a pre-installed, shared key. is an unsigned integer field, whose length is - 3, and which contains the cryptographic signature. The version of this TLV, specified in this section, 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 13. Herberg & Clausen Expires August 3, 2012 [Page 10] Internet-Draft MANET Cryptographical Signature TLV January 2012 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 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 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 implicitly available parameter is the length of the signature, which is - 3, and which depends on the choice of the cryptographic function. 12.2. Considerations for Calculating the Signature In the following, considerations are listed, which MUST be applied when calculating the signature for Packet, Message and Address SIGNATURE TLVs, respectively. 12.2.1. Packet SIGNATURE TLV When determining the for a Packet, the signature is calculated over the three fields , and (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, in accordance with Section 8.1. 12.2.2. Message SIGNATURE TLV When determining the for a message, the signature is calculated over the three fields , , and (in that order), concatenated with the entire message. The considerations in Section 9.1 MUST be applied. 12.2.3. Address Block SIGNATURE TLV When determining the for an address, the signature is calculated over the three fields , , and (in that order), concatenated with the address, concatenated with any other values, for example, any other address block TLV that is associated with that address. A MANET routing protocol or MANET routing protocol extension using Herberg & Clausen Expires August 3, 2012 [Page 11] Internet-Draft MANET Cryptographical Signature TLV January 2012 Address Block SIGNATURE TLVs MUST specify how to include any such concatenated attribute of the address in the verification process of the signature. The considerations in Section 10.2 MUST be applied. 12.3. Example of a Signed Message The sample message depicted in Figure 1 is derived from appendix D of [RFC5444]. The message contains a SIGNATURE Message TLV, with the value representing a 16 octet long signature of the whole message. The type extension of the Message TLV is 1, for the specific decomposition of a signature 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 = 40 | Msg. Orig Addr| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Message Originator Address (cont) | Hop Limit | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Hop Count | Message Sequence Number | Msg. TLV Block| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Length = 30 | SIGNATURE | MTLVF = 144 | MTLVExt = 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Value Len = 19 | Hash Func | Crypto Func | Key Index | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Signature Value | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Signature Value (cont) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Signature Value (cont) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Signature Value (cont) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: Example message with signature 13. IANA Considerations 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, Herberg & Clausen Expires August 3, 2012 [Page 12] Internet-Draft MANET Cryptographical Signature TLV January 2012 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 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: o Creation of type extension registries for these TLV types with initial values as in Table 1 to Table 3. IANA is requested to assign the same numerical value to the Packet TLV, Message TLV and Address Block TLV types with the same name. The following terms are used with the meanings defined in [BCP26]: "Namespace", "Assigned Value", "Registration", "Unassigned", "Reserved", "Hierarchical Allocation", and "Designated Expert". The following policies are used with the meanings defined in [BCP26]: "Private Use", "Expert Review", and "Standards Action". 13.1. 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 Block TLVs SHOULD be numbered identically. 13.2. Packet TLV Type Registrations IANA is requested to make allocations from the "Packet TLV Types" namespace of [RFC5444] for the Packet TLVs specified in Table 1. Herberg & Clausen Expires August 3, 2012 [Page 13] Internet-Draft MANET Cryptographical Signature TLV January 2012 +-----------+------+-----------+------------------------------------+ | Name | Type | Type | Description | | | | Extension | | +-----------+------+-----------+------------------------------------+ | SIGNATURE | TBD1 | 0 | Signature of a packet | | | | 1 | Signature, decomposed into | | | | | cryptographic function over a hash | | | | | value, as specified in Section 12 | | | | | in this document. | | | | 2-251 | Expert Review | | | | 252-255 | Experimental Use | | TIMESTAMP | TBD2 | 0 | Unsigned timestamp of arbitrary | | | | | length, given by the TLV length | | | | | field. The MANET routing protocol | | | | | has to define how to interpret | | | | | this timestamp | | | | 1-251 | Expert Review | | | | 252-255 | Experimental Use | +-----------+------+-----------+------------------------------------+ Table 1: Packet TLV types 13.3. Message TLV Type Registrations IANA is requested to make allocations from the "Message TLV Types" namespace of [RFC5444] for the Message TLVs specified in Table 2. +-----------+------+-----------+------------------------------------+ | Name | Type | Type | Description | | | | Extension | | +-----------+------+-----------+------------------------------------+ | SIGNATURE | TBD3 | 0 | Signature of a message | | | | 1 | Signature, decomposed into | | | | | cryptographic function over a hash | | | | | value, as specified in Section 12 | | | | | in this document. | | | | 2-251 | Expert Review | | | | 252-255 | Experimental Use | | TIMESTAMP | TBD4 | 0 | Unsigned timestamp of arbitrary | | | | | length, given by the TLV length | | | | | field. | | | | 1-251 | Expert Review | | | | 252-255 | Experimental Use | +-----------+------+-----------+------------------------------------+ Table 2: Message TLV types Herberg & Clausen Expires August 3, 2012 [Page 14] Internet-Draft MANET Cryptographical Signature TLV January 2012 13.4. Address Block TLV Type Registrations IANA is requested to make allocations from the "Address Block TLV Types" namespace of [RFC5444] for the Packet TLVs specified in Table 3. +-----------+------+-----------+------------------------------------+ | Name | Type | Type | Description | | | | Extension | | +-----------+------+-----------+------------------------------------+ | SIGNATURE | TBD5 | 0 | Signature of an object (e.g. an | | | | | address) | | | | 1 | Signature, decomposed into | | | | | cryptographic function over a hash | | | | | value, as specified in Section 12 | | | | | in this document. | | | | 2-251 | Expert Review | | | | 252-255 | Experimental Use | | TIMESTAMP | TBD6 | 0 | Unsigned timestamp of arbitrary | | | | | length, given by the TLV length | | | | | field. | | | | 1-251 | Expert Review | | | | 252-255 | Experimental Use | +-----------+------+-----------+------------------------------------+ Table 3: Address Block TLV types 13.5. Hash Function IANA is requested to create a new registry for hash functions that can be used when creating a signature, 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 | | 1-251 | | Expert Review | | 252-255 | | Experimental Use | +-------------+-----------+-----------------------------------------+ Table 4: Hash-Function registry Herberg & Clausen Expires August 3, 2012 [Page 15] Internet-Draft MANET Cryptographical Signature TLV January 2012 13.6. Cryptographic Algorithm IANA is requested to create a new registry for the cryptographic function, 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 | | 1-251 | | 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 signatures 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 the usage as well as the security that is attained by the cryptographic signatures of a message or a packet. As an example, a MANET 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). 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. Herberg & Clausen Expires August 3, 2012 [Page 16] Internet-Draft MANET Cryptographical Signature TLV January 2012 16. References 16.1. 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. 16.2. Informative References [OLSRv2] Clausen, T., Dearlove, C., and P. Jacquet, "The Optimized Link State Routing Protocol version 2", work in progress draft-ietf-manet-olsrv2-13.txt, October 2011. [RFC6130] Clausen, T., Dean, J., and C. Dearlove, "MANET Neighborhood Discovery Protocol (NHDP)", RFC 6130, March 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 Expires August 3, 2012 [Page 17]