TLS Elliptic Curve Cipher Suites with SHA-256/384 and AES Galois Counter Mode (GCM)
RFC 5289
Document | Type |
RFC - Proposed Standard
(August 2008; No errata)
Status changed by status-change-uplifting-rfc5289-to-ps
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Author | Eric Rescorla | ||
Last updated | 2018-07-11 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized bibtex | ||
Reviews | |||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 5289 (Proposed Standard) | |
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Pasi Eronen | ||
Send notices to | (None) |
Network Working Group E. Rescorla Request for Comments: 5289 RTFM, Inc. Category: Informational August 2008 TLS Elliptic Curve Cipher Suites with SHA-256/384 and AES Galois Counter Mode (GCM) Status of This Memo This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited. Abstract RFC 4492 describes elliptic curve cipher suites for Transport Layer Security (TLS). However, all those cipher suites use HMAC-SHA-1 as their Message Authentication Code (MAC) algorithm. This document describes sixteen new cipher suites for TLS that specify stronger MAC algorithms. Eight use Hashed Message Authentication Code (HMAC) with SHA-256 or SHA-384, and eight use AES in Galois Counter Mode (GCM). Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Conventions Used in This Document . . . . . . . . . . . . . . . 2 3. Cipher Suites . . . . . . . . . . . . . . . . . . . . . . . . . 2 3.1. HMAC-Based Cipher Suites . . . . . . . . . . . . . . . . . 2 3.2. Galois Counter Mode-Based Cipher Suites . . . . . . . . . . 3 4. Security Considerations . . . . . . . . . . . . . . . . . . . . 3 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 3 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 4 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 4 7.1. Normative References . . . . . . . . . . . . . . . . . . . 4 7.2. Informative References . . . . . . . . . . . . . . . . . . 5 Rescorla Informational [Page 1] RFC 5289 TLS ECC New MAC August 2008 1. Introduction RFC 4492 [RFC4492] describes Elliptic Curve Cryptography (ECC) cipher suites for Transport Layer Security (TLS). However, all of the RFC 4492 suites use HMAC-SHA1 as their MAC algorithm. Due to recent analytic work on SHA-1 [Wang05], the IETF is gradually moving away from SHA-1 and towards stronger hash algorithms. This document specifies TLS ECC cipher suites that use SHA-256 and SHA-384 [SHS] rather than SHA-1. TLS 1.2 [RFC5246], adds support for authenticated encryption with additional data (AEAD) cipher modes [RFC5116]. This document also specifies a set of ECC cipher suites using one such mode, Galois Counter Mode (GCM) [GCM]. Another document [RFC5288] provides support for GCM with other key establishment methods. 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. Cipher Suites This document defines 16 new cipher suites to be added to TLS. All use Elliptic Curve Cryptography for key exchange and digital signature, as defined in RFC 4492. 3.1. HMAC-Based Cipher Suites The first eight cipher suites use AES [AES] in Cipher Block Chaining (CBC) [CBC] mode with an HMAC-based MAC: CipherSuite TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256 = {0xC0,0x23}; CipherSuite TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384 = {0xC0,0x24}; CipherSuite TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA256 = {0xC0,0x25}; CipherSuite TLS_ECDH_ECDSA_WITH_AES_256_CBC_SHA384 = {0xC0,0x26}; CipherSuite TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 = {0xC0,0x27}; CipherSuite TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 = {0xC0,0x28}; CipherSuite TLS_ECDH_RSA_WITH_AES_128_CBC_SHA256 = {0xC0,0x29}; CipherSuite TLS_ECDH_RSA_WITH_AES_256_CBC_SHA384 = {0xC0,0x2A}; These eight cipher suites are the same as the corresponding cipher suites in RFC 4492 (with names ending in "_SHA" in place of "_SHA256" or "_SHA384"), except for the MAC and Pseudo Random Function (PRF) algorithms. Rescorla Informational [Page 2] RFC 5289 TLS ECC New MAC August 2008 These SHALL be as follows: o For cipher suites ending with _SHA256, the PRF is the TLS PRF [RFC5246] with SHA-256 as the hash function. The MAC is HMAC [RFC2104] with SHA-256 as the hash function. o For cipher suites ending with _SHA384, the PRF is the TLS PRF [RFC5246] with SHA-384 as the hash function. The MAC is HMAC [RFC2104] with SHA-384 as the hash function. 3.2. Galois Counter Mode-Based Cipher Suites The second eight cipher suites use the same asymmetric algorithms as those in the previous section but use the new authenticated encryption modes defined in TLS 1.2 with AES in Galois Counter Mode (GCM) [GCM]: CipherSuite TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 = {0xC0,0x2B};Show full document text