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diff --git a/doc/protocol/draft-rescorla-tls-suiteb-02.txt b/doc/protocol/draft-rescorla-tls-suiteb-02.txt new file mode 100644 index 0000000000..a8ac2cf2b3 --- /dev/null +++ b/doc/protocol/draft-rescorla-tls-suiteb-02.txt @@ -0,0 +1,449 @@ + + + +Network Working Group M. Salter +Internet-Draft National Security Agency +Intended status: Informational E. Rescorla +Expires: October 16, 2008 Network Resonance + April 14, 2008 + + + Suite B Cipher Suites for TLS + draft-rescorla-tls-suiteb-02.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 October 16, 2008. + +Copyright Notice + + Copyright (C) The IETF Trust (2008). + +Abstract + + The United States Government has published guidelines for "NSA Suite + B Cryptography" dated July, 2005, which defines cryptographic + algorithm polcy for national security applications. This document + defines a profile of TLS which is conformant with Suite B. + + + + + + +Salter & Rescorla Expires October 16, 2008 [Page 1] + +Internet-Draft Suite B for TLS April 2008 + + +Table of Contents + + 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 + 2. Conventions Used In This Document . . . . . . . . . . . . . . . 3 + 3. Suite B Requirements . . . . . . . . . . . . . . . . . . . . . 3 + 4. Suite B Compliance Requirements . . . . . . . . . . . . . . . . 4 + 4.1. Security Levels . . . . . . . . . . . . . . . . . . . . . . 4 + 4.2. Acceptable Curves . . . . . . . . . . . . . . . . . . . . . 5 + 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 + 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 + 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6 + 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6 + 8.1. Normative References . . . . . . . . . . . . . . . . . . . 6 + 8.2. Informative References . . . . . . . . . . . . . . . . . . 7 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7 + Intellectual Property and Copyright Statements . . . . . . . . . . 8 + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +Salter & Rescorla Expires October 16, 2008 [Page 2] + +Internet-Draft Suite B for TLS April 2008 + + +1. Introduction + + In July, 2005 the National Security Agency posted "Fact Sheet, NSA + Suite B Cryptography" which stated: + + To complement the existing policy for the use of the Advanced + Encryption Standard (AES) to protect national security systems + and information as specified in The National Policy on the use of + the Advanced Encryption Standard (AES) to Protect National + Security Systems and National Security Information (CNSSP-15), + the National Security Agency (NSA) announced Suite B Cryptography + at the 2005 RSA Conference. In addition to the AES, Suite B + includes cryptographic algorithms for hashing, digital + signatures, and key exchange. + + Suite B only specifies the cryptographic algorithms to be + used. Many other factors need to be addressed in determining + whether a particular device implementing a particular set of + cryptographic algorithms should be used to satisfy a particular + requirement. + + Among those factors are "requirements for interoperability both + domestically and internationally". + + This document is a profile of of TLS 1.2 [I-D.ietf-tls-rfc4346-bis] + and of the cipher suites defined in [I-D.ietf-tls-ecc-new-mac], but + does not itself define any new cipher suites. This profile requires + TLS 1.2. + + +2. 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]. + + +3. Suite B Requirements + + The "Suite B Fact Sheet" requires that key establishment and + authentication algorithms be based on Elliptic Curve Cryptography, + that the encryption algorithm be AES [AES], and that the function + used for key derivation and data integrity be SHA [SHS]. It defines + two security levels, of 128 and 192 bits. + + In particular it states: + + + + + +Salter & Rescorla Expires October 16, 2008 [Page 3] + +Internet-Draft Suite B for TLS April 2008 + + + SUITE B includes: + + Encryption: Advanced Encryption Standard (AES) - + FIPS 197 (with keys sizes of 128 and 256 + bits) + + Digital Signature: Elliptic Curve Digital Signature Algorithm - + FIPS 186-2 (using the curves with 256 and + 384-bit prime moduli) + + Key Exchange: Elliptic Curve Diffie-Hellman or Elliptic + Curve MQV Draft NIST Special Publication + 800-56 (using the curves with 256 and + 384-bit prime moduli) + + Hashing: Secure Hash Algorithm - FIPS 180-2 + (using SHA-256 and SHA-384) + + All implementations of Suite B must, at a minimum, include AES + with 128-bit keys, the 256-bit prime modulus elliptic curve and + SHA-256 as a common mode for widespread interoperability. + + The 128-bit security level corresponds to an elliptic curve size of + 256 bits, AES-128, and SHA-256. The 192-bit security level + corresponds to an elliptic curve size of 384 bits, AES-256, and SHA- + 384. + + +4. Suite B Compliance Requirements + + To be considered "Suite B compatible" at least one of the Galois + Counter Mode (GCM) CipherSuites defined in [I-D.ietf-tls-ecc-new-mac] + MUST be negotiated. In compliance with the guidance in the Suite B + Fact Sheet every TLS implementation of Suite B SHOULD implement + TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256. + +4.1. Security Levels + + As described in Section 1, Suite B specifies two security levels, 128 + and 192 bit. The following table lists the security levels for each + cipher suite: + + + + + + + + + + +Salter & Rescorla Expires October 16, 2008 [Page 4] + +Internet-Draft Suite B for TLS April 2008 + + + +-----------------------------------------+----------------+ + | Cipher Suite | Security Level | + +-----------------------------------------+----------------+ + | TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 | 128 | + | TLS_ECDH_ECDSA_WITH_AES_128_GCM_SHA256 | 128 | + | TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 | 192 | + | TLS_ECDH_ECDSA_WITH_AES_256_GCM_SHA384 | 192 | + +-----------------------------------------+----------------+ + +4.2. Acceptable Curves + + RFC 4492 defines a variety of elliptic curves. For cipher suites + defined in this specification, only secp256r1 (23) or secp384r1 (24) + may be used. (These are the same curves that appear in FIPS 186-2 + [DSS] as P-256 and P-384, respectively.) For cipher suites at the + 128-bit security level, secp256r1 MUST be used. For cipher suites at + the 192-bit security level, secp384r1 MUST be used. RFC 4492 + requires that uncompressed (0) form be supported. + ansiX962_compressed_prime(1) point formats MAY be supported. + + Clients desiring to negotiate only a Suite B-compliant connection + MUST generate a "Supported Elliptic Curves Extension" containing only + the allowed curves. These curves MUST match the cipher suite + security levels being offered. Clients which are willing to do both + Suite B-compliant and non-Suite B-compliant connections MAY omit the + extension or send the extension but offer other curves as well as the + appropriate Suite B ones. + + Servers desiring to negotiate a Suite B-compliant connection SHOULD + check for the presence of the extension, but MUST NOT negotiate + inappropriate curves even if they are offered by the client. This + allows a Client which is willing to do either Suite B-compliant or + non-Suite B-compliant modes to interoperate with a server which will + only do Suite B-compliant modes. If the client does not advertise an + acceptable curve, the server MUST generate a fatal + "handshake_failure" alert and terminate the connection. Clients MUST + check the chosen curve to make sure it is acceptable. + + +5. Security Considerations + + Most of the security considerations for this document are described + in TLS 1.2 [I-D.ietf-tls-rfc4346-bis], RFC 4492 [RFC4492], + [I-D.ietf-tls-rsa-aes-gcm], and [I-D.ietf-tls-ecc-new-mac]. Readers + should consult those documents. + + In order to meet the goal of a consistent security level for the + entire cipher suite, in Suite B mode TLS implementations MUST ONLY + + + +Salter & Rescorla Expires October 16, 2008 [Page 5] + +Internet-Draft Suite B for TLS April 2008 + + + use the curves defined in Section 4.2. Otherwise, it is possible to + have a set of symmetric algorithms with much weaker or stronger + security properties than the asymmetric (ECC) algorithms. + + +6. IANA Considerations + + This document defines no actions for IANA. + + +7. Acknowledgements + + This work was supported by the US Department of Defense. + + +8. References + +8.1. Normative References + + [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate + Requirement Levels", BCP 14, RFC 2119, March 1997. + + [RFC4492] Blake-Wilson, S., Bolyard, N., Gupta, V., Hawk, C., and B. + Moeller, "Elliptic Curve Cryptography (ECC) Cipher Suites + for Transport Layer Security (TLS)", RFC 4492, May 2006. + + [I-D.ietf-tls-rfc4346-bis] + Dierks, T. and E. Rescorla, "The Transport Layer Security + (TLS) Protocol Version 1.2", draft-ietf-tls-rfc4346-bis-10 + (work in progress), March 2008. + + [I-D.ietf-tls-ecc-new-mac] + Rescorla, E., "TLS Elliptic Curve Cipher Suites with SHA- + 256/384 and AES Galois Counter Mode", + draft-ietf-tls-ecc-new-mac-04 (work in progress), + February 2008. + + [AES] National Institute of Standards and Technology, + "Specification for the Advanced Encryption Standard + (AES)", FIPS 197, November 2001. + + [SHS] National Institute of Standards and Technology, "Secure + Hash Standard", FIPS 180-2, August 2002. + + [DSS] National Institute of Standards and Technology, "Digital + Signature Standard", FIPS 186-2, January 2000. + + + + + +Salter & Rescorla Expires October 16, 2008 [Page 6] + +Internet-Draft Suite B for TLS April 2008 + + +8.2. Informative References + + [I-D.ietf-tls-rsa-aes-gcm] + Salowey, J., Choudhury, A., and D. McGrew, "AES-GCM Cipher + Suites for TLS", draft-ietf-tls-rsa-aes-gcm-02 (work in + progress), February 2008. + + +Authors' Addresses + + Margaret Salter + National Security Agency + 9800 Savage Rd. + Fort Meade 20755-6709 + USA + + Email: msalter@restarea.ncsc.mil + + + Eric Rescorla + Network Resonance + 2064 Edgewood Drive + Palo Alto 94303 + USA + + Email: ekr@rtfm.com + + + + + + + + + + + + + + + + + + + + + + + + + +Salter & Rescorla Expires October 16, 2008 [Page 7] + +Internet-Draft Suite B for TLS April 2008 + + +Full 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. + + 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 + THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED + WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. + + +Intellectual Property + + 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. + + +Acknowledgment + + Funding for the RFC Editor function is provided by the IETF + Administrative Support Activity (IASA). + + + + + +Salter & Rescorla Expires October 16, 2008 [Page 8] + + |