Individual Submission D. Black Internet Draft EMC Intended status: Proposed Standard D. McGrew Expires: July 2008 Cisco Systems Updates: 4306 February 15, 2008 Using Authenticated Encryption Algorithms with the Encrypted Payload of the Internet Key Exchange version 2 (IKEv2) Protocol draft-black-ipsec-ikev2-aead-modes-00.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html This Internet-Draft will expire on July 30, 2008. Copyright Notice Copyright (C) The IETF Trust (2008). Abstract Black & McGrew Expires August 15, 2008 [Page 1]
Internet-Draft Authenticated Encryption and IKEv2 February 2008 An authenticated encryption algorithm combines encryption and integrity into a single operation; such algorithms may also be referred to as combined modes of an encryption cipher or as combined mode algorithms. This document describes the use of authenticated encryption algorithms with the Encrypted Payload of the Internet Key Exchange version 2 (IKEv2) protocol. The use of two specific authenticated encryption algorithms with the IKEv2 Encrypted Payload is also described; these two algorithms are the Advanced Encryption Standard (AES) in Galois/Counter Mode (AES GCM) and AES in Counter with CBC-MAC Mode (AES CCM). Additional documents may describe use of other authenticated encryption algorithms with the IKEv2 Encrypted Payload. Conventions used in this document The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. The symbols or variables that designate authenticated encryption and decryption operation inputs and outputs (K, N, P, A, and C) are the same as used in [RFC5116]. Table of Contents 1. Introduction...................................................3 2. Structure of this Document.....................................4 3. IKEv2 Encrypted Payload Data...................................4 3.1. AES GCM and AES CCM Initialization Vector (IV)............6 3.2. AES GCM and AES CCM Ciphertext (C) Construction...........7 4. AES GCM and AES CCM Nonce (N) Format...........................7 5. Associated Data (A)............................................7 5.1. Associated Data (A) Construction..........................8 5.2. Data Integrity Coverage...................................8 6. AES GCM and AES CCM Encrypted Payload Expansion................9 7. IKEv2 Conventions for AES GCM and AES CCM......................9 7.1. Keying Material and Salt Values...........................9 7.2. IKEv2 Identifiers........................................10 7.3. Key Length...............................................10 8. Algorithm Selection...........................................10 9. Test Vectors..................................................11 10. Security Considerations......................................11 11. IANA Considerations..........................................11 12. Acknowledgments..............................................11 13. References...................................................12 13.1. Normative References....................................12 Black & McGrew Expires August 15, 2008 [Page 2]
Internet-Draft Authenticated Encryption and IKEv2 February 2008 13.2. Informative References..................................12 Author's Addresses...............................................13 Intellectual Property Statement..................................13 Disclaimer of Validity...........................................13 1. Introduction An authenticated encryption algorithm [RFC5116] combines encryption and integrity into a single operation on plaintext data to produce ciphertext that includes an integrity check. The integrity check may be an Integrity Check Value (ICV) that is logically distinct from the encrypted data or the integrity check may be incorporated into the encrypted data that is produced. Authenticated encryption algorithms may also be referred to as combined modes of operation of a block cipher or as combined mode algorithms. An authenticated encryption with associated data (AEAD) algorithm also provides integrity protection for additional data that is associated with the plaintext, but which is left unencrypted. This document describes the use of authenticated encryption algorithms with the Encrypted Payload of the Internet Key Exchange version 2 (IKEv2) protocol. The use of two specific authenticated encryption algorithms with the IKEv2 Encrypted Payload is also described; the two algorithms are the Advanced Encryption Standard (AES) in Galois/Counter Mode (AES GCM) and AES in Counter with CBC- MAC Mode (AES CCM). Version 1 of the Internet Key Exchange protocol (IKEv1) [RFC2409] is based on the Internet Security Association and Key Management Protocol (ISAKMP) [RFC2408]. The E (Encryption) bit in the ISAKMP header specifies that all payloads following the header are encrypted, but any data integrity verification of those payloads is handled by a separate Hash Payload or Signature Payload (see sections 3.1, 3.11 and 3.12 of [RFC2408]). This separation of encryption from data integrity protection prevents use of authenticated encryption with IKEv1, thus limiting initial specifications of AES combined mode usage for IPsec to the Encapsulating Security Payload (ESP) [RFC2406]. The current version of ESP is version 2, ESPv2 [RFC4303]. Version 2 of the Internet Key Exchange Protocol (IKEv2) [RFC4306] employs an Encrypted Payload that is based on the design of ESP. The IKEv2 Encrypted Payload associates encryption and data integrity protection in a fashion that makes it possible to use authenticated encryption algorithms. Black & McGrew Expires August 15, 2008 [Page 3]
Internet-Draft Authenticated Encryption and IKEv2 February 2008 2. Structure of this Document This document is based on the RFCs that describe the usage of AES GCM [RFC4106] and AES CCM [RFC4309] with ESP, and hence the introductory material and specification of the modes in those documents are not repeated here. The structure of this document follows the structure of those documents; each section of this document indicates which section of those two documents it corresponds to and calls out any significant changes of which implementers should be aware. Significant portions of the text of this document have been adapted from those two documents. This document is based on the authenticated encryption interfaces, notation and terminology described in [RFC5116]. An important departure from [RFC4106] and [RFC4309] is that these two RFCs describe separate ciphertext and integrity check outputs of the encryption operation, whereas [RFC5116] specifies a single Ciphertext (C) output that includes an integrity check. The latter more general approach encompasses authenticated encryption algorithms that produce a single expanded ciphertext output into which the integrity check is incorporated, rather than producing separate ciphertext and integrity check outputs. For AES GCM and AES CCM, the [RFC5116] Ciphertext (C) output of encryption consists of the [RFC4106] or [RFC4309] ciphertext output concatenated with the [RFC4106] or [RFC4309] Integrity Check Value (ICV) output. This document does not modify the AES GCM and AES CCM authenticated encryption algorithms. 3. IKEv2 Encrypted Payload Data This section is based on [RFC5116] and Section 3.14 of [RFC4306]. For use of authenticated encryption algorithms with the IKEv2 Encrypted Payload, this section updates [RFC4306] to replace Figure 21 in Section 3.14 and the text that follows it through the end of that section with the contents of this section. In addition Section 3.14 of [RFC4306] is also updated to allow use of a single authenticated encryption algorithm instead of a block cipher and a separate integrity check algorithm. In contrast, Sections 3.1 and 3.2 of this document are specific to the AES GCM and AES CCM algorithms and hence do not update [RFC4306]. The IKEv2 Encrypted Payload Data structure applies to all authenticated encryption algorithms, and it is the same structure that is used with ESP. When an authenticated encryption algorithm is used, the IKEv2 Encrypted Payload is composed of the payload header Black & McGrew Expires August 15, 2008 [Page 4]
Internet-Draft Authenticated Encryption and IKEv2 February 2008 fields, followed by an Initialization Vector (IV) field and Ciphertext (C) field that includes an integrity check as shown in Figure 1. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ! Next Payload !C! RESERVED ! Payload Length ! +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ! Initialization Vector ! ! (length is specified by authenticated encryption algorithm) ! +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Ciphertext ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1. IKEv2 Encrypted Payload Data for Authenticated Encryption The Next Payload field, C bit and Payload length fields are unchanged from [RFC4306]. The contents of the Initialization Vector (IV) field are specified by the authenticated encryption algorithm; see Section 3.1 (below) for AES GCM and AES CCM. When decrypting an Encrypted Payload, a receiver constructs the nonce based on the IV from that data structure, using rules that are specific to the AEAD algorithm. The Ciphertext field is the output of an authenticated encryption operation (see Section 2.1 of [RFC5116]) on the following inputs: o The secret key (K) is the cipher key obtained from the SK_ei or SK_er key, whichever is appropriate, see [RFC4306]. The authenticated encryption algorithm describes how to obtain the cipher key from SK_ei or SK_er; for AES GCM and AES CCM, see Section 7.1 (below). o The nonce (N) is specified by the authenticated encryption algorithm; for AES GCM and AES CCM, see Section 4 (below). o The plaintext (P) consists of the concatenation of the IKE Payloads to be encrypted with the Padding (if any) and the Pad Length, as shown in Figure 2 (below). o The associated data (A) is described in Section 5 (below). Black & McGrew Expires August 15, 2008 [Page 5]
Internet-Draft Authenticated Encryption and IKEv2 February 2008 Recall that the Ciphertext utput of AEAD algorithms, as defined by [RFC5116], incorporates data that allows for checks on the integrity and authenticity of the Ciphertext and associated data check data. Thus, there is no need for a separate Integrity Check Value (ICV) field in the IKEv2 Encrypted Payload Data structure. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ IKE Payloads to be Encrypted ~ + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ! ! Padding (0-255 octets) ! +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ ! ! Pad Length ! +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2. IKEv2 Encrypted Payload Plaintext (P) for Authenticated Encryption The IKE Payloads are as specified in [RFC4306]. Padding MAY contain any value chosen by the sender. Pad Length is the number of octets in the Padding field. The length of the Padding field MUST be chosen so that the number of octets in the Encrypted Payload is a multiple of four, in order to satisfy IKEv2 data alignment needs. The sender SHOULD set the Pad Length to the minimum value that makes the combination of the Payloads, the Padding, and the Pad Length fields a multiple of four octets in length, but the recipient MUST accept any length that results in proper alignment. 3.1. AES GCM and AES CCM Initialization Vector (IV) This section is based on Section 3.1 of [RFC4106] and Section 3.1 of [RFC4309]. The Initialization Vector requirements are common to AES GCM and AES CCM, and are the same as the requirements for ESP. The Initialization Vector (IV) MUST be eight octets, the AES block size. The IV MUST be chosen by the encryptor in a manner that ensures that the same IV value is used only once for a given key. The encryptor can generate the IV in any manner that ensures uniqueness. Common approaches to IV generation include incrementing a counter for each packet and linear feedback shift registers (LFSRs). Black & McGrew Expires August 15, 2008 [Page 6]
Internet-Draft Authenticated Encryption and IKEv2 February 2008 3.2. AES GCM and AES CCM Ciphertext (C) Construction This section is based on Section 6 of [RFC4106] and Section 3.1 of [RFC4309] with generalizations to match the interfaces specified in [RFC5116]. The constructions for AES GCM and AES CCM are different, but in each case, the construction is the same as used for ESP. For AES GCM and AES CCM, the Ciphertext field consists of the output of the AEAD encryption algorithm. (Note that this field incorporates integrity-check data.) The AES GCM ICV consists solely of the AES GCM Authentication Tag. Implementations MUST support a full-length 16-octet ICV, MAY support 8 or 12 octet ICVs, and MUST NOT support other ICV lengths. AES CCM provides an encrypted ICV. Implementations MUST support ICV sizes of 8 octets and 16 octets. Implementations MAY also support 12 octet ICVs and MUST NOT support other ICV lengths. 4. AES GCM and AES CCM Nonce (N) Format Specific AEAD algorithms MAY use different nonce formats, though they SHOULD use the following format, which is intended to be the default. With this format, the nonces are partially implicit, see Section 3.2.1 of [RFC5116]. The implicit portion of the nonce is the salt; the salt is not included in the IKEv2 Encrypted Payload. The explicit portion of the nonce is the IV that is included in the IKEv2 Encrypted Payload. For use of AES GCM with the IKEv2 Encrypted Payload, the default nonce format MUST be used. Note that this format matches the one specified in Section 4 of [RFC4106], which ensures compatibility between the use of AES GCM in IKEv2 and ESP. All of the requirements of Section 4 of [RFC4106] apply to use of AES GCM with the IKEv2 Encrypted Payload. For use of AES CCM with the IKEv2 Encrypted Payload, the nonce format MUST be the format specified in Section 4 of [RFC4309]. All of the requirements of Section 4 of [RFC4309] apply to use of AES CCM with the IKEv2 Encrypted Payload. 5. Associated Data (A) This section is based on Section 3.1 of [RFC4106] and Section 3.1 of [RFC4309], both of which refer to associated data as Additional Authenticated Data (AAD). The associated data construction described in this section applies to all authenticated encryption algorithms, Black & McGrew Expires August 15, 2008 [Page 7]
Internet-Draft Authenticated Encryption and IKEv2 February 2008 but differs from the construction used with ESP because IKEv2 requires different data integrity coverage. 5.1. Associated Data (A) Construction The associated data (A) MUST consist of the partial contents of the IKEv2 message starting from the first octet of the Fixed IKE Header through the last octet of the Payload Header of the Encrypted Payload (i.e., the fourth octet of the Encrypted Payload), as shown in Figure 3. This includes any Payloads that are between the Fixed IKE Header and the Encrypted Payload. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ IKEv2 Header ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Unencrypted IKE Payloads ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ! Next Payload !C! RESERVED ! Payload Length ! +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3. IKEv2 Encrypted Payload Data for Combined Modes The Initialization Vector and Ciphertext fields shown in Figure 1 (above) MUST NOT be included in the associated data. 5.2. Data Integrity Coverage The data integrity coverage of the IKEv2 Encrypted Payload encompasses the entire IKEv2 message that contains the Encrypted Payload. When an authenticated encryption algorithm is used with the Encrypted Payload, this coverage is realized as follows: 1. The associated data (A) covers the portion of the IKEv2 message starting from the first octet of the Fixed IKE Header through the last octet of the Payload Header of the Encrypted Payload (fourth octet of the Encrypted Payload). This includes any Payloads between the Fixed IKE Header and the Encrypted Payload. The Encrypted Payload is always the last payload in an IKEv2 message [RFC4306]. 2. The IV is an input to the authenticated encryption algorithm's integrity check. A successful integrity check at the receiver verifies that the correct IV was used, providing data integrity coverage for the IV. Black & McGrew Expires August 15, 2008 [Page 8]
Internet-Draft Authenticated Encryption and IKEv2 February 2008 3. The plaintext (IKE Payloads, Padding and Pad Length) is covered by the authenticated encryption algorithm's integrity check. 6. AES GCM and AES CCM Encrypted Payload Expansion The expansion described in Section 7 of [RFC4106] and Section 6 of [RFC4309] applies to use of the AES GCM and AES CCM combined modes with the IKEv2 Encrypted Payload. See Section 7 of [RFC4106] and Section 6 of [RFC4309]. 7. IKEv2 Conventions for AES GCM and AES CCM This section describes the conventions used to generate keying material and salt values for use with AES GCM and AES CCM using the IKEv2 [RFC4306] protocol. The identifiers and attributes needed to use AES GCM and AES CCM with the IKEv2 Encrypted Payload are also specified. 7.1. Keying Material and Salt Values This section is based on Section 8.1 of [RFC4106] and Section 7.1 of [RFC4309]. The Keying Material and Salt Values for AES GCM and AES CCM are different, but have the same structure as the Keying Material and Salt Values used with ESP. IKEv2 makes use of a pseudo-random function (PRF) to derive keying material. The PRF is used iteratively to derive keying material of arbitrary size, from which keying material for specific uses is extracted without regard to PRF output boundaries, see Section 2.14 of [RFC4306]. This subsection describes how the key derivation specified in Section 2.14 of [RFC4306] is used to obtain keying material for AES GCM and AES CCM. When AES GCM or AES CCM is used with the IKEv2 Encrypted Payload, the SK_ai and SK_ar integrity protection keys are not used; each key MUST be treated as having a size of zero (0) octets. The size of each of the SK_ei and SK_er encryption keys includes additional salt bytes. The size and format of each of the SK_ei and SK_er encryption keys MUST be: o For AES GCM, each encryption key has the size and format of the "KEYMAT requested" material specified in Section 8.1 of [RFC4106] for the AES key size being used. For example, if the AES key size is 128 bits, each encryption key is 20 octets, consisting of a 16 octet AES cipher key followed by 4 octets of salt. Black & McGrew Expires August 15, 2008 [Page 9]
Internet-Draft Authenticated Encryption and IKEv2 February 2008 o For AES CCM, each key has the size and format of the "KEYMAT requested" material specified in Section 7.1 of [RFC4309] for the AES key size being used. For example, if the AES key size is 128 bits, each encryption key is 19 octets, consisting of a 16 octet AES cipher key followed by 3 octets of salt. 7.2. IKEv2 Identifiers This section is unique to IKEv2 Encrypted Payload usage of AES GCM and AES CCM. It reuses the identifiers used to negotiate ESP usage of AES GCM and AES CCM. The following identifiers previously allocated by IANA are used to negotiate use of AES GCM and AES CCM as the Encryption (ENCR) Transform for IKEv2 (i.e., for use with the IKEv2 Encrypted Payload): 16 for AES CCM with a 16-octet ICV; and 20 for AES GCM with a 16 octet ICV. The identifiers 14, 15, 18, and 19 MUST NOT be used. These identifiers are associated with transforms with shorter ICVs. 7.3. Key Length This section is based on Section 8.4 of [RFC4106] and Section 7.4 of [RFC4309]. The Key Length requirements are common to AES GCM and AES CCM and are identical to the key length requirements for ESP. Because the AES supports three key lengths, the Key Length attribute MUST be specified when any of the identifiers for AES GCM or AES CCM specified in Section 7.2 of this document is used. The Key Length attribute MUST have a value of 128 or 256. 8. Algorithm Selection This section applies to the use of any authenticated encryption algorithm with the IKEv2 Encrypted Payload and is unique to that usage. IKEv2 (section 3.3.3 of [RFC4306]) specifies that both an encryption algorithm and an integrity checking algorithm are required for an IKE SA (Security Association). This document updates [RFC4306] by qualifying that statement to say that when an authenticated encryption algorithm is selected as the encryption algorithm for any SA (IKE or ESP), an integrity algorithm MUST NOT be selected for that SA. This document further updates [RFC4306] to require that if all Black & McGrew Expires August 15, 2008 [Page 10]
Internet-Draft Authenticated Encryption and IKEv2 February 2008 of the encryption algorithms in any proposal are authenticated encryption algorithms, then the proposal MUST NOT propose any integrity transforms. 9. Test Vectors See Section 9 of [RFC4106] and Section 8 of [RFC4309] for references that provide AES GCM and AES CCM test vectors. 10. Security Considerations For authenticated encryption security considerations, see [RFC5116]; there are important security considerations that are discussed outside the security considerations section of that document. The security considerations for use of AES GCM and AES CCM with ESP apply to use of these algorithms with the IKEv2 Encrypted Payload, see Section 10 of [RFC4106] and Section 9 of [RFC4309]. Use of AES GCM and AES CCM with IKEv2 does not create additional security considerations beyond those for use of AES GCM and AES CCM with ESP. For IKEv2 security considerations, see Section 5 of [RFC4306]. 11. IANA Considerations This document has no actions for IANA. The Encryption Transform identifiers specified in Section 7.2 have been previously assigned by IANA for use with ESP. This document extends their usage to IKEv2 for the Encrypted Payload. 12. Acknowledgments See Section 13 of [RFC4106] and Section 12 of [RFC4309] for AES GCM and AES CCM acknowledgments. Also, we thank Charlie Kaufman, Pasi Eronen, and Tero Kivinen for their comprehensive reviews of this document. This document was prepared using 2-Word-v2.0.template.dot, created by Joe Touch. Black & McGrew Expires August 15, 2008 [Page 11]
Internet-Draft Authenticated Encryption and IKEv2 February 2008 13. References 13.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC4106] Viega, J. and D. McGrew, "The Use of Galois/Counter Mode (GCM) in IPsec Encapsulating Security Payload (ESP)", RFC 4106, June 2005. [RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", RFC 4303, December 2005. [RFC4306] Kaufman, C. (Editor), "Internet Key Exchange (IKEv2) Protocol", RFC 4306, December 2005. [RFC4309] Housley, R., "Using Advanced Encryption Standard (AES) CCM Mode with IPsec Encapsulating Security Payload (ESP)", RFC 4309, December 2005. [RFC5116] McGrew, D., "An Interface and Algorithms for Authenticated Encryption", RFC 5116, to appear. 13.2. Informative References [RFC2406] Kent, S. and Atkinson, R., "IP Encapsulating Security Payload (ESP)", RFC 2406, November 1998. [RFC2408] Maughan, D., M. Schertler, M. Schneider and J. Turner, " Internet Security Association and Key Management Protocol (ISAKMP)", RFC 2408, November 1998. [RFC2409] Harkins, D. and D. Carrel, "The Internet Key Exchange (IKE)", RFC 2409, November 1998. Black & McGrew Expires August 15, 2008 [Page 12]
Internet-Draft Authenticated Encryption and IKEv2 February 2008 Author's Addresses David L. Black EMC Corporation 176 South Street Hopkinton, MA 10748 Phone: +1 (508) 293-7953 Email: black_david@emc.com David A. McGrew Cisco Systems, Inc. 510 McCarthy Blvd. Milpitas, CA 95035 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Disclaimer of Validity This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF Black & McGrew Expires August 15, 2008 [Page 13]
Internet-Draft Authenticated Encryption and IKEv2 February 2008 THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Copyright Statement Copyright (C) The IETF Trust (2008). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Black & McGrew Expires August 15, 2008 [Page 14]
