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diff --git a/doc/protocol/draft-ietf-tls-srp-14.txt b/doc/protocol/draft-ietf-tls-srp-14.txt deleted file mode 100644 index 5ebc432932..0000000000 --- a/doc/protocol/draft-ietf-tls-srp-14.txt +++ /dev/null @@ -1,1457 +0,0 @@ - - - -TLS Working Group D. Taylor -Internet-Draft Independent -Expires: December 15, 2007 T. Wu - Stanford University - N. Mavrogiannopoulos - T. Perrin - Independent - June 13, 2007 - - - Using SRP for TLS Authentication - draft-ietf-tls-srp-14 - -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 December 15, 2007. - -Copyright Notice - - Copyright (C) The IETF Trust (2007). - - - - - - - - - - -Taylor, et al. Expires December 15, 2007 [Page 1] - -Internet-Draft Using SRP for TLS Authentication June 2007 - - -Abstract - - This memo presents a technique for using the Secure Remote Password - protocol as an authentication method for the Transport Layer Security - protocol. - - -Table of Contents - - 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 2. SRP Authentication in TLS . . . . . . . . . . . . . . . . . . 4 - 2.1. Notation and Terminology . . . . . . . . . . . . . . . . . 4 - 2.2. Handshake Protocol Overview . . . . . . . . . . . . . . . 4 - 2.3. Text Preparation . . . . . . . . . . . . . . . . . . . . . 5 - 2.4. SRP Verifier Creation . . . . . . . . . . . . . . . . . . 5 - 2.5. Changes to the Handshake Message Contents . . . . . . . . 5 - 2.5.1. Client Hello . . . . . . . . . . . . . . . . . . . . . 5 - 2.5.2. Server Certificate . . . . . . . . . . . . . . . . . . 7 - 2.5.3. Server Key Exchange . . . . . . . . . . . . . . . . . 7 - 2.5.4. Client Key Exchange . . . . . . . . . . . . . . . . . 8 - 2.6. Calculating the Pre-master Secret . . . . . . . . . . . . 8 - 2.7. Cipher Suite Definitions . . . . . . . . . . . . . . . . . 8 - 2.8. New Message Structures . . . . . . . . . . . . . . . . . . 9 - 2.8.1. Client Hello . . . . . . . . . . . . . . . . . . . . . 9 - 2.8.2. Server Key Exchange . . . . . . . . . . . . . . . . . 10 - 2.8.3. Client Key Exchange . . . . . . . . . . . . . . . . . 10 - 2.9. Error Alerts . . . . . . . . . . . . . . . . . . . . . . . 11 - 3. Security Considerations . . . . . . . . . . . . . . . . . . . 12 - 3.1. General Considerations for Implementors . . . . . . . . . 12 - 3.2. Accepting Group Parameters . . . . . . . . . . . . . . . . 12 - 3.3. Protocol Characteristics . . . . . . . . . . . . . . . . . 12 - 3.4. Hash Function Considerations . . . . . . . . . . . . . . . 13 - 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 - 5. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15 - 5.1. Normative References . . . . . . . . . . . . . . . . . . . 15 - 5.2. Informative References . . . . . . . . . . . . . . . . . . 15 - Appendix A. SRP Group Parameters . . . . . . . . . . . . . . . . 17 - Appendix B. SRP Test Vectors . . . . . . . . . . . . . . . . . . 22 - Appendix C. Acknowledgements . . . . . . . . . . . . . . . . . . 24 - Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 25 - Intellectual Property and Copyright Statements . . . . . . . . . . 26 - - - - - - - - - - -Taylor, et al. Expires December 15, 2007 [Page 2] - -Internet-Draft Using SRP for TLS Authentication June 2007 - - -1. Introduction - - At the time of writing TLS [TLS] uses public key certificates, pre- - shared keys, or Kerberos for authentication. - - These authentication methods do not seem well suited to certain - applications now being adapted to use TLS ([IMAP] for example). - Given that many protocols are designed to use the user name and - password method of authentication, being able to safely use user - names and passwords provides an easier route to additional security. - - SRP ([SRP], [SRP-6]) is an authentication method that allows the use - of user names and passwords over unencrypted channels without - revealing the password to an eavesdropper. SRP also supplies a - shared secret at the end of the authentication sequence that can be - used to generate encryption keys. - - This document describes the use of the SRP authentication method for - TLS. - - 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 RFC 2119 [REQ]. - - - - - - - - - - - - - - - - - - - - - - - - - - - - -Taylor, et al. Expires December 15, 2007 [Page 3] - -Internet-Draft Using SRP for TLS Authentication June 2007 - - -2. SRP Authentication in TLS - -2.1. Notation and Terminology - - The version of SRP used here is sometimes referred to as "SRP-6" - [SRP-6]. This version is a slight improvement over "SRP-3", which - was described in [SRP] and [SRP-RFC]. - - This document uses the variable names defined in [SRP-6]: - - N, g: group parameters (prime and generator) - - s: salt - - B, b: server's public and private values - - A, a: client's public and private values - - I: user name (aka "identity") - - P: password - - v: verifier - - k: SRP-6 multiplier - - The | symbol indicates string concatenation, the ^ operator is the - exponentiation operation, and the % operator is the integer remainder - operation. - - Conversion between integers and byte-strings assumes the most- - significant bytes are stored first, as per [TLS] and [SRP-RFC]. In - the following text, if a conversion from integer to byte-string is - implicit, the most-significant byte in the resultant byte-string MUST - be non-zero. If a conversion is explicitly specified with the - operator PAD(), the integer will first be implicitly converted, then - the resultant byte-string will be left-padded with zeros (if - necessary) until its length equals the implicitly-converted length of - N. - -2.2. Handshake Protocol Overview - - The advent of [SRP-6] allows the SRP protocol to be implemented using - the standard sequence of handshake messages defined in [TLS]. - - The parameters to various messages are given in the following - diagram. - - - - -Taylor, et al. Expires December 15, 2007 [Page 4] - -Internet-Draft Using SRP for TLS Authentication June 2007 - - - Client Server - - Client Hello (I) --------> - Server Hello - Certificate* - Server Key Exchange (N, g, s, B) - <-------- Server Hello Done - Client Key Exchange (A) --------> - [Change cipher spec] - Finished --------> - [Change cipher spec] - <-------- Finished - - Application Data <-------> Application Data - - * Indicates an optional message which is not always sent. - - Figure 1 - -2.3. Text Preparation - - The user name and password strings SHALL be UTF-8 encoded Unicode, - prepared using the [SASLPREP] profile of [STRINGPREP]. - -2.4. SRP Verifier Creation - - The verifier is calculated as described in section 3 of [SRP-RFC]. - We give the algorithm here for convenience. - - The verifier (v) is computed based on the salt (s), user name (I), - password (P), and group parameters (N, g). The computation uses the - [SHA1] hash algorithm: - - x = SHA1(s | SHA1(I | ":" | P)) - v = g^x % N - -2.5. Changes to the Handshake Message Contents - - This section describes the changes to the TLS handshake message - contents when SRP is being used for authentication. The definitions - of the new message contents and the on-the-wire changes are given in - Section 2.8. - -2.5.1. Client Hello - - The user name is appended to the standard client hello message using - the extension mechanism defined in [TLSEXT] (see Section 2.8.1). - This user name extension is henceforth called the "SRP extension". - - - -Taylor, et al. Expires December 15, 2007 [Page 5] - -Internet-Draft Using SRP for TLS Authentication June 2007 - - - The following subsections give details of its use. - -2.5.1.1. Session Resumption - - When a client attempts to resume a session that uses SRP - authentication, the client MUST include the SRP extension in the - client hello message, in case the server cannot or will not allow - session resumption, meaning a full handshake is required. - - If the server does agree to resume an existing session the server - MUST ignore the information in the SRP extension of the client hello - message, except for its inclusion in the finished message hashes. - This is to ensure attackers cannot replace the authenticated identity - without supplying the proper authentication information. - -2.5.1.2. Missing SRP Extension - - The client may offer SRP ciphersuites in the hello message but omit - the SRP extension. If the server would like to select an SRP - ciphersuite in this case, the server SHOULD return a fatal - "unknown_psk_identity" alert (see Section 2.9) immediately after - processing the client hello message. - - A client receiving this alert MAY choose to reconnect and resend the - hello message, this time with the SRP extension. This allows the - client to advertise that it supports SRP, but not have to prompt the - user for his user name and password, nor expose the user name in the - clear, unless necessary. - -2.5.1.3. Unknown SRP Username - - If the server doesn't have a verifier for the user name in the SRP - extension, the server MAY abort the handshake with an - "unknown_psk_identity" alert (see Section 2.9). Alternatively, if - the server wishes to hide the fact that this user name doesn't have a - verifier, the server MAY simulate the protocol as if a verifier - existed, but then reject the client's finished message with a - "bad_record_mac" alert, as if the password was incorrect. - - To simulate the existence of an entry for each user name, the server - must consistently return the same salt (s) and group (N, g) values - for the same user name. For example, the server could store a secret - "seed key" and then use HMAC-SHA1(seed_key, "salt" | user_name) to - generate the salts [HMAC]. For B, the server can return a random - value between 1 and N-1 inclusive. However, the server should take - care to simulate computation delays. One way to do this is to - generate a fake verifier using the "seed key" approach, and then - proceed with the protocol as usual. - - - -Taylor, et al. Expires December 15, 2007 [Page 6] - -Internet-Draft Using SRP for TLS Authentication June 2007 - - -2.5.2. Server Certificate - - The server MUST send a certificate if it agrees to an SRP cipher - suite that requires the server to provide additional authentication - in the form of a digital signature. See Section 2.7 for details of - which ciphersuites defined in this document require a server - certificate to be sent. - -2.5.3. Server Key Exchange - - The server key exchange message contains the prime (N), the generator - (g), and the salt value (s) read from the SRP password file based on - the user name (I) received in the client hello extension. - - The server key exchange message also contains the server's public - value (B). The server calculates this value as B = k*v + g^b % N, - where b is a random number which SHOULD be at least 256 bits in - length, and k = SHA1(N | PAD(g)). - - If the server has sent a certificate message, the server key exchange - message MUST be signed. - - The group parameters (N, g) sent in this message MUST have N as a - safe prime (a prime of the form N=2q+1, where q is also prime). The - integers from 1 to N-1 will form a group under multiplication % N, - and g MUST be a generator of this group. In addition, the group - parameters MUST NOT be specially chosen to allow efficient - computation of discrete logarithms. - - The SRP group parameters in Appendix A satisfy the above - requirements, so the client SHOULD accept any parameters from this - Appendix which have large enough N values to meet her security - requirements. - - The client MAY accept other group parameters from the server, if the - client has reason to believe these parameters satisfy the above - requirements, and the parameters have large enough N values. For - example, if the parameters transmitted by the server match parameters - on a "known-good" list, the client may choose to accept them. See - Section 3 for additional security considerations relevant to the - acceptance of the group parameters. - - Group parameters that are not accepted via one of the above methods - MUST be rejected with an "insufficient_security" alert (see - Section 2.9). - - The client MUST abort the handshake with an "illegal_parameter" alert - if B % N = 0. - - - -Taylor, et al. Expires December 15, 2007 [Page 7] - -Internet-Draft Using SRP for TLS Authentication June 2007 - - -2.5.4. Client Key Exchange - - The client key exchange message carries the client's public value - (A). The client calculates this value as A = g^a % N, where a is a - random number which SHOULD be at least 256 bits in length. - - The server MUST abort the handshake with an "illegal_parameter" alert - if A % N = 0. - -2.6. Calculating the Pre-master Secret - - The pre-master secret is calculated by the client as follows: - - I, P = <read from user> - N, g, s, B = <read from server> - a = random() - A = g^a % N - u = SHA1(PAD(A) | PAD(B)) - k = SHA1(N | PAD(g)) - x = SHA1(s | SHA1(I | ":" | P)) - <premaster secret> = (B - (k * g^x)) ^ (a + (u * x)) % N - - The pre-master secret is calculated by the server as follows: - - N, g, s, v = <read from password file> - b = random() - k = SHA1(N | PAD(g)) - B = k*v + g^b % N - A = <read from client> - u = SHA1(PAD(A) | PAD(B)) - <premaster secret> = (A * v^u) ^ b % N - - The finished messages perform the same function as the client and - server evidence messages (M1 and M2) specified in [SRP-RFC]. If - either the client or the server calculate an incorrect premaster - secret, the finished messages will fail to decrypt properly, and the - other party will return a "bad_record_mac" alert. - - If a client application receives a "bad_record_mac" alert when - performing an SRP handshake, it should inform the user that the - entered user name and password are incorrect. - -2.7. Cipher Suite Definitions - - The following cipher suites are added by this draft. The usage of - AES ciphersuites is as defined in [AESCIPH]. - - - - - -Taylor, et al. Expires December 15, 2007 [Page 8] - -Internet-Draft Using SRP for TLS Authentication June 2007 - - - CipherSuite TLS_SRP_SHA_WITH_3DES_EDE_CBC_SHA = { 0xC0,0xTBD2 }; - - CipherSuite TLS_SRP_SHA_RSA_WITH_3DES_EDE_CBC_SHA = { 0xC0,0xTBD3 - }; - - CipherSuite TLS_SRP_SHA_DSS_WITH_3DES_EDE_CBC_SHA = { 0xC0,0xTBD4 - }; - - CipherSuite TLS_SRP_SHA_WITH_AES_128_CBC_SHA = { 0xC0,0xTBD5 }; - - CipherSuite TLS_SRP_SHA_RSA_WITH_AES_128_CBC_SHA = { 0xC0,0xTBD6 - }; - - CipherSuite TLS_SRP_SHA_DSS_WITH_AES_128_CBC_SHA = { 0xC0,0xTBD7 - }; - - CipherSuite TLS_SRP_SHA_WITH_AES_256_CBC_SHA = { 0xC0,0xTBD8 }; - - CipherSuite TLS_SRP_SHA_RSA_WITH_AES_256_CBC_SHA = { 0xC0,0xTBD9 - }; - - CipherSuite TLS_SRP_SHA_DSS_WITH_AES_256_CBC_SHA = { 0xC0,0xTBD10 - }; - - Cipher suites that begin with TLS_SRP_SHA_RSA or TLS_SRP_SHA_DSS - require the server to send a certificate message containing a - certificate with the specified type of public key, and to sign the - server key exchange message using a matching private key. - - Cipher suites that do not include a digital signature algorithm - identifier assume the server is authenticated by its possesion of the - SRP verifier. - - Implementations conforming to this specification MUST implement the - TLS_SRP_SHA_WITH_3DES_EDE_CBC_SHA ciphersuite, SHOULD implement the - TLS_SRP_SHA_WITH_AES_128_CBC_SHA and TLS_SRP_SHA_WITH_AES_256_CBC_SHA - ciphersuites, and MAY implement the remaining ciphersuites. - -2.8. New Message Structures - - This section shows the structure of the messages passed during a - handshake that uses SRP for authentication. The representation - language used is the same as that used in [TLS]. - -2.8.1. Client Hello - - A new extension "srp" with value TBD1, has been added to the - enumerated ExtensionType defined in [TLSEXT]. This value MUST be - - - -Taylor, et al. Expires December 15, 2007 [Page 9] - -Internet-Draft Using SRP for TLS Authentication June 2007 - - - used as the extension number for the SRP extension. - - The "extension_data" field of the SRP extension SHALL contain: - - opaque srp_I<1..2^8-1>; - - where srp_I is the user name, encoded per Section 2.3. - -2.8.2. Server Key Exchange - - A new value, "srp", has been added to the enumerated - KeyExchangeAlgorithm originally defined in [TLS]. - - When the value of KeyExchangeAlgorithm is set to "srp", the server's - SRP parameters are sent in the server key exchange message, encoded - in a ServerSRPParams structure. - - If a certificate is sent to the client the server key exchange - message must be signed. - - enum { rsa, diffie_hellman, srp } KeyExchangeAlgorithm; - - struct { - select (KeyExchangeAlgorithm) { - case diffie_hellman: - ServerDHParams params; - Signature signed_params; - case rsa: - ServerRSAParams params; - Signature signed_params; - case srp: /* new entry */ - ServerSRPParams params; - Signature signed_params; - }; - } ServerKeyExchange; - - struct { - opaque srp_N<1..2^16-1>; - opaque srp_g<1..2^16-1>; - opaque srp_s<1..2^8-1>; - opaque srp_B<1..2^16-1>; - } ServerSRPParams; /* SRP parameters */ - -2.8.3. Client Key Exchange - - When the value of KeyExchangeAlgorithm is set to "srp", the client's - public value (A) is sent in the client key exchange message, encoded - in a ClientSRPPublic structure. - - - -Taylor, et al. Expires December 15, 2007 [Page 10] - -Internet-Draft Using SRP for TLS Authentication June 2007 - - - struct { - select (KeyExchangeAlgorithm) { - case rsa: EncryptedPreMasterSecret; - case diffie_hellman: ClientDiffieHellmanPublic; - case srp: ClientSRPPublic; /* new entry */ - } exchange_keys; - } ClientKeyExchange; - - struct { - opaque srp_A<1..2^16-1>; - } ClientSRPPublic; - -2.9. Error Alerts - - This document introduces four new uses of alerts: - - o "unknown_psk_identity" (115) - this alert MAY be sent by a server - that would like to select an offered SRP ciphersuite, if the SRP - extension is absent from the client's hello message. This alert - is always fatal. See Section 2.5.1.2 for details. - - o "unknown_psk_identity" (115) - this alert MAY be sent by a server - that receives an unknown user name. This alert is always fatal. - See Section 2.5.1.3 for details. - - o "insufficient_security" (71) - this alert MUST be sent by a client - that receives unknown or untrusted (N, g) values. This alert is - always fatal. See Section 2.5.3 for details. - - o "illegal_parameter" (47) - this alert MUST be sent by a client or - server that receives a key exchange message with A % N = 0 or B % - N = 0. This alert is always fatal. See Section 2.5.3 and - Section 2.5.4 and for details. - - The "insufficient_security" and "illegal_parameter" alerts are - defined in [TLS]. The "unknown_psk_identity" alert is defined in - [PSK]. - - - - - - - - - - - - - - -Taylor, et al. Expires December 15, 2007 [Page 11] - -Internet-Draft Using SRP for TLS Authentication June 2007 - - -3. Security Considerations - -3.1. General Considerations for Implementors - - The checks described in Section 2.5.3 and Section 2.5.4 on the - received values for A and B are CRUCIAL for security and MUST be - performed. - - The private values a and b SHOULD be at least 256 bit random numbers, - to give approximately 128 bits of security against certain methods of - calculating discrete logarithms. See [TLS] section D.1 for advice on - choosing cryptographically secure random numbers. - -3.2. Accepting Group Parameters - - An attacker who could calculate discrete logarithms % N could - compromise user passwords, and could also compromise the the - confidentiality and integrity of TLS sessions. Clients MUST ensure - that the received parameter N is large enough to make calculating - discrete logarithms computationally infeasible. - - An attacker may try to send a prime value N which is large enough to - be secure, but which has a special form for which the attacker can - more easily compute discrete logarithms (e.g., using the algorithm - discussed in [TRAPDOOR]). If the client executes the protocol using - such a prime, the client's password could be compromised. Because of - the difficulty of checking for such primes in real-time, clients - SHOULD only accept group parameters that come from a trusted source, - such as those listed in Appendix A, or parameters configured locally - by a trusted administrator. - -3.3. Protocol Characteristics - - If an attacker learns a user's SRP verifier (e.g., by gaining access - to a server's password file), the attacker can masquerade as the real - server to that user, and can also attempt a dictionary attack to - recover that user's password. - - An attacker could repeatedly contact an SRP server and try to guess a - legitimate user's password. Servers SHOULD take steps to prevent - this, such as limiting the rate of authentication attempts from a - particular IP address, or against a particular user name. - - The client's user name is sent in the clear in the Client Hello - message. To avoid sending the user name in the clear, the client - could first open a conventional anonymous or server-authenticated - connection, then renegotiate an SRP-authenticated connection with the - handshake protected by the first connection. - - - -Taylor, et al. Expires December 15, 2007 [Page 12] - -Internet-Draft Using SRP for TLS Authentication June 2007 - - - If the client receives an "unknown_psk_identity" alert in response to - a client hello, this alert may have been inserted by an attacker. - The client should be careful about making any decisions, or forming - any conclusions, based on receiving this alert. - - It is possible to choose a (user name, password) pair such that the - resulting verifier will also match other, related, (user name, - password) pairs. Thus, anyone using verifiers should be careful not - to assume that only a single (user name, password) pair matches the - verifier. - -3.4. Hash Function Considerations - - This protocol uses SHA-1 to derive several values: - - o u prevents an attacker who learns a user's verifier from being - able to authenticate as that user (see [SRP-6]). - - o k prevents an attacker who can select group parameters from being - able to launch a 2-for-1 guessing attack (see [SRP-6]). - - o x contains the user's password mixed with a salt. - - Cryptanalytic attacks against SHA-1 which only affect its collision- - resistance do not compromise these uses. If attacks against SHA-1 - are discovered which do compromise these uses, new ciphersuites - should be specified to use a different hash algorithm. - - In this situation, clients could send a Client Hello message - containing new and/or old SRP ciphersuites along with a single SRP - extension. The server could then select the appropriate ciphersuite - based on the type of verifier it has stored for this user. - - - - - - - - - - - - - - - - - - - -Taylor, et al. Expires December 15, 2007 [Page 13] - -Internet-Draft Using SRP for TLS Authentication June 2007 - - -4. IANA Considerations - - This document defines a new TLS extension "srp" (value TBD1), whose - value is to be assigned from the TLS ExtensionType Registry defined - in [TLSEXT]. - - This document defines nine new ciphersuites, whose values are to be - assigned from the TLS Cipher Suite registry defined in [TLS]. - - CipherSuite TLS_SRP_SHA_WITH_3DES_EDE_CBC_SHA = { 0xC0,0xTBD2 }; - - CipherSuite TLS_SRP_SHA_RSA_WITH_3DES_EDE_CBC_SHA = { 0xC0,0xTBD3 - }; - - CipherSuite TLS_SRP_SHA_DSS_WITH_3DES_EDE_CBC_SHA = { 0xC0,0xTBD4 - }; - - CipherSuite TLS_SRP_SHA_WITH_AES_128_CBC_SHA = { 0xC0,0xTBD5 }; - - CipherSuite TLS_SRP_SHA_RSA_WITH_AES_128_CBC_SHA = { 0xC0,0xTBD6 - }; - - CipherSuite TLS_SRP_SHA_DSS_WITH_AES_128_CBC_SHA = { 0xC0,0xTBD7 - }; - - CipherSuite TLS_SRP_SHA_WITH_AES_256_CBC_SHA = { 0xC0,0xTBD8 }; - - CipherSuite TLS_SRP_SHA_RSA_WITH_AES_256_CBC_SHA = { 0xC0,0xTBD9 - }; - - CipherSuite TLS_SRP_SHA_DSS_WITH_AES_256_CBC_SHA = { 0xC0,0xTBD10 - }; - - - - - - - - - - - - - - - - - - - -Taylor, et al. Expires December 15, 2007 [Page 14] - -Internet-Draft Using SRP for TLS Authentication June 2007 - - -5. References - -5.1. Normative References - - [REQ] Bradner, S., "Key words for use in RFCs to Indicate - Requirement Levels", BCP 14, RFC 2119, March 1997. - - [TLS] Dierks, T. and E. Rescorla, "The TLS Protocol version - 1.1", RFC 4346, April 2006. - - [TLSEXT] Blake-Wilson, S., Nystrom, M., Hopwood, D., Mikkelsen, J., - and T. Wright, "Transport Layer Security (TLS) - Extensions", RFC 4366, April 2006. - - [STRINGPREP] - Hoffman, P. and M. Blanchet, "Preparation of - Internationalized Strings ("stringprep")", RFC 3454, - December 2002. - - [SASLPREP] - Zeilenga, K., "SASLprep: Stringprep profile for user names - and passwords", RFC 4013, February 2005. - - [SRP-RFC] Wu, T., "The SRP Authentication and Key Exchange System", - RFC 2945, September 2000. - - [SHA1] "Secure Hash Standard (SHS)", FIPS 180-2, August 2002. - - [HMAC] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed- - Hashing for Message Authentication", RFC 2104, - February 1997. - - [AESCIPH] Chown, P., "Advanced Encryption Standard (AES) - Ciphersuites for Transport Layer Security (TLS)", - RFC 3268, June 2002. - - [PSK] Eronen, P. and H. Tschofenig, "Pre-Shared Key Ciphersuites - for Transport Layer Security (TLS)", RFC 4279, - December 2005. - - [MODP] Kivinen, T. and M. Kojo, "More Modular Exponentiation - (MODP) Diffie-Hellman groups for Internet Key Exchange - (IKE)", RFC 3526, May 2003. - -5.2. Informative References - - [IMAP] Newman, C., "Using TLS with IMAP, POP3 and ACAP", - RFC 2595, June 1999. - - - -Taylor, et al. Expires December 15, 2007 [Page 15] - -Internet-Draft Using SRP for TLS Authentication June 2007 - - - [SRP-6] Wu, T., "SRP-6: Improvements and Refinements to the Secure - Remote Password Protocol", Submission to IEEE P1363.2 - working group, October 2002, - <http://grouper.ieee.org/groups/1363/>. - - [SRP] Wu, T., "The Secure Remote Password Protocol", Proceedings - of the 1998 Internet Society Network and Distributed - System Security Symposium pp. 97-111, March 1998. - - [TRAPDOOR] - Gordon, D., "Designing and Detecting Trapdoors for - Discrete Log Cryptosystems", Springer-Verlag Advances in - Cryptology - Crypto '92, pp. 66-75, 1993. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -Taylor, et al. Expires December 15, 2007 [Page 16] - -Internet-Draft Using SRP for TLS Authentication June 2007 - - -Appendix A. SRP Group Parameters - - The 1024, 1536, and 2048-bit groups are taken from software developed - by Tom Wu and Eugene Jhong for the Stanford SRP distribution, and - subsequently proven to be prime. The larger primes are taken from - [MODP], but generators have been calculated that are primitive roots - of N, unlike the generators in [MODP]. - - The 1024-bit and 1536-bit groups MUST be supported. - - 1. 1024-bit Group - - The hexadecimal value for the prime is: - - EEAF0AB9 ADB38DD6 9C33F80A FA8FC5E8 60726187 75FF3C0B 9EA2314C - 9C256576 D674DF74 96EA81D3 383B4813 D692C6E0 E0D5D8E2 50B98BE4 - 8E495C1D 6089DAD1 5DC7D7B4 6154D6B6 CE8EF4AD 69B15D49 82559B29 - 7BCF1885 C529F566 660E57EC 68EDBC3C 05726CC0 2FD4CBF4 976EAA9A - FD5138FE 8376435B 9FC61D2F C0EB06E3 - - - The generator is: 2. - - - 2. 1536-bit Group - - The hexadecimal value for the prime is: - - 9DEF3CAF B939277A B1F12A86 17A47BBB DBA51DF4 99AC4C80 BEEEA961 - 4B19CC4D 5F4F5F55 6E27CBDE 51C6A94B E4607A29 1558903B A0D0F843 - 80B655BB 9A22E8DC DF028A7C EC67F0D0 8134B1C8 B9798914 9B609E0B - E3BAB63D 47548381 DBC5B1FC 764E3F4B 53DD9DA1 158BFD3E 2B9C8CF5 - 6EDF0195 39349627 DB2FD53D 24B7C486 65772E43 7D6C7F8C E442734A - F7CCB7AE 837C264A E3A9BEB8 7F8A2FE9 B8B5292E 5A021FFF 5E91479E - 8CE7A28C 2442C6F3 15180F93 499A234D CF76E3FE D135F9BB - - - The generator is: 2. - - - 3. 2048-bit Group - - The hexadecimal value for the prime is: - - AC6BDB41 324A9A9B F166DE5E 1389582F AF72B665 1987EE07 FC319294 - 3DB56050 A37329CB B4A099ED 8193E075 7767A13D D52312AB 4B03310D - CD7F48A9 DA04FD50 E8083969 EDB767B0 CF609517 9A163AB3 661A05FB - D5FAAAE8 2918A996 2F0B93B8 55F97993 EC975EEA A80D740A DBF4FF74 - - - -Taylor, et al. Expires December 15, 2007 [Page 17] - -Internet-Draft Using SRP for TLS Authentication June 2007 - - - 7359D041 D5C33EA7 1D281E44 6B14773B CA97B43A 23FB8016 76BD207A - 436C6481 F1D2B907 8717461A 5B9D32E6 88F87748 544523B5 24B0D57D - 5EA77A27 75D2ECFA 032CFBDB F52FB378 61602790 04E57AE6 AF874E73 - 03CE5329 9CCC041C 7BC308D8 2A5698F3 A8D0C382 71AE35F8 E9DBFBB6 - 94B5C803 D89F7AE4 35DE236D 525F5475 9B65E372 FCD68EF2 0FA7111F - 9E4AFF73 - - - The generator is: 2. - - - 4. 3072-bit Group - - This prime is: 2^3072 - 2^3008 - 1 + 2^64 * { [2^2942 pi] + - 1690314 } - - Its hexadecimal value is: - - FFFFFFFF FFFFFFFF C90FDAA2 2168C234 C4C6628B 80DC1CD1 29024E08 - 8A67CC74 020BBEA6 3B139B22 514A0879 8E3404DD EF9519B3 CD3A431B - 302B0A6D F25F1437 4FE1356D 6D51C245 E485B576 625E7EC6 F44C42E9 - A637ED6B 0BFF5CB6 F406B7ED EE386BFB 5A899FA5 AE9F2411 7C4B1FE6 - 49286651 ECE45B3D C2007CB8 A163BF05 98DA4836 1C55D39A 69163FA8 - FD24CF5F 83655D23 DCA3AD96 1C62F356 208552BB 9ED52907 7096966D - 670C354E 4ABC9804 F1746C08 CA18217C 32905E46 2E36CE3B E39E772C - 180E8603 9B2783A2 EC07A28F B5C55DF0 6F4C52C9 DE2BCBF6 95581718 - 3995497C EA956AE5 15D22618 98FA0510 15728E5A 8AAAC42D AD33170D - 04507A33 A85521AB DF1CBA64 ECFB8504 58DBEF0A 8AEA7157 5D060C7D - B3970F85 A6E1E4C7 ABF5AE8C DB0933D7 1E8C94E0 4A25619D CEE3D226 - 1AD2EE6B F12FFA06 D98A0864 D8760273 3EC86A64 521F2B18 177B200C - BBE11757 7A615D6C 770988C0 BAD946E2 08E24FA0 74E5AB31 43DB5BFC - E0FD108E 4B82D120 A93AD2CA FFFFFFFF FFFFFFFF - - - The generator is: 5. - - - 5. 4096-bit Group - - This prime is: 2^4096 - 2^4032 - 1 + 2^64 * { [2^3966 pi] + - 240904 } - - Its hexadecimal value is: - - FFFFFFFF FFFFFFFF C90FDAA2 2168C234 C4C6628B 80DC1CD1 29024E08 - 8A67CC74 020BBEA6 3B139B22 514A0879 8E3404DD EF9519B3 CD3A431B - 302B0A6D F25F1437 4FE1356D 6D51C245 E485B576 625E7EC6 F44C42E9 - A637ED6B 0BFF5CB6 F406B7ED EE386BFB 5A899FA5 AE9F2411 7C4B1FE6 - - - -Taylor, et al. Expires December 15, 2007 [Page 18] - -Internet-Draft Using SRP for TLS Authentication June 2007 - - - 49286651 ECE45B3D C2007CB8 A163BF05 98DA4836 1C55D39A 69163FA8 - FD24CF5F 83655D23 DCA3AD96 1C62F356 208552BB 9ED52907 7096966D - 670C354E 4ABC9804 F1746C08 CA18217C 32905E46 2E36CE3B E39E772C - 180E8603 9B2783A2 EC07A28F B5C55DF0 6F4C52C9 DE2BCBF6 95581718 - 3995497C EA956AE5 15D22618 98FA0510 15728E5A 8AAAC42D AD33170D - 04507A33 A85521AB DF1CBA64 ECFB8504 58DBEF0A 8AEA7157 5D060C7D - B3970F85 A6E1E4C7 ABF5AE8C DB0933D7 1E8C94E0 4A25619D CEE3D226 - 1AD2EE6B F12FFA06 D98A0864 D8760273 3EC86A64 521F2B18 177B200C - BBE11757 7A615D6C 770988C0 BAD946E2 08E24FA0 74E5AB31 43DB5BFC - E0FD108E 4B82D120 A9210801 1A723C12 A787E6D7 88719A10 BDBA5B26 - 99C32718 6AF4E23C 1A946834 B6150BDA 2583E9CA 2AD44CE8 DBBBC2DB - 04DE8EF9 2E8EFC14 1FBECAA6 287C5947 4E6BC05D 99B2964F A090C3A2 - 233BA186 515BE7ED 1F612970 CEE2D7AF B81BDD76 2170481C D0069127 - D5B05AA9 93B4EA98 8D8FDDC1 86FFB7DC 90A6C08F 4DF435C9 34063199 - FFFFFFFF FFFFFFFF - - - The generator is: 5. - - - 6. 6144-bit Group - - This prime is: 2^6144 - 2^6080 - 1 + 2^64 * { [2^6014 pi] + - 929484 } - - Its hexadecimal value is: - - FFFFFFFF FFFFFFFF C90FDAA2 2168C234 C4C6628B 80DC1CD1 29024E08 - 8A67CC74 020BBEA6 3B139B22 514A0879 8E3404DD EF9519B3 CD3A431B - 302B0A6D F25F1437 4FE1356D 6D51C245 E485B576 625E7EC6 F44C42E9 - A637ED6B 0BFF5CB6 F406B7ED EE386BFB 5A899FA5 AE9F2411 7C4B1FE6 - 49286651 ECE45B3D C2007CB8 A163BF05 98DA4836 1C55D39A 69163FA8 - FD24CF5F 83655D23 DCA3AD96 1C62F356 208552BB 9ED52907 7096966D - 670C354E 4ABC9804 F1746C08 CA18217C 32905E46 2E36CE3B E39E772C - 180E8603 9B2783A2 EC07A28F B5C55DF0 6F4C52C9 DE2BCBF6 95581718 - 3995497C EA956AE5 15D22618 98FA0510 15728E5A 8AAAC42D AD33170D - 04507A33 A85521AB DF1CBA64 ECFB8504 58DBEF0A 8AEA7157 5D060C7D - B3970F85 A6E1E4C7 ABF5AE8C DB0933D7 1E8C94E0 4A25619D CEE3D226 - 1AD2EE6B F12FFA06 D98A0864 D8760273 3EC86A64 521F2B18 177B200C - BBE11757 7A615D6C 770988C0 BAD946E2 08E24FA0 74E5AB31 43DB5BFC - E0FD108E 4B82D120 A9210801 1A723C12 A787E6D7 88719A10 BDBA5B26 - 99C32718 6AF4E23C 1A946834 B6150BDA 2583E9CA 2AD44CE8 DBBBC2DB - 04DE8EF9 2E8EFC14 1FBECAA6 287C5947 4E6BC05D 99B2964F A090C3A2 - 233BA186 515BE7ED 1F612970 CEE2D7AF B81BDD76 2170481C D0069127 - D5B05AA9 93B4EA98 8D8FDDC1 86FFB7DC 90A6C08F 4DF435C9 34028492 - 36C3FAB4 D27C7026 C1D4DCB2 602646DE C9751E76 3DBA37BD F8FF9406 - AD9E530E E5DB382F 413001AE B06A53ED 9027D831 179727B0 865A8918 - DA3EDBEB CF9B14ED 44CE6CBA CED4BB1B DB7F1447 E6CC254B 33205151 - - - -Taylor, et al. Expires December 15, 2007 [Page 19] - -Internet-Draft Using SRP for TLS Authentication June 2007 - - - 2BD7AF42 6FB8F401 378CD2BF 5983CA01 C64B92EC F032EA15 D1721D03 - F482D7CE 6E74FEF6 D55E702F 46980C82 B5A84031 900B1C9E 59E7C97F - BEC7E8F3 23A97A7E 36CC88BE 0F1D45B7 FF585AC5 4BD407B2 2B4154AA - CC8F6D7E BF48E1D8 14CC5ED2 0F8037E0 A79715EE F29BE328 06A1D58B - B7C5DA76 F550AA3D 8A1FBFF0 EB19CCB1 A313D55C DA56C9EC 2EF29632 - 387FE8D7 6E3C0468 043E8F66 3F4860EE 12BF2D5B 0B7474D6 E694F91E - 6DCC4024 FFFFFFFF FFFFFFFF - - - The generator is: 5. - - - 7. 8192-bit Group - - This prime is: 2^8192 - 2^8128 - 1 + 2^64 * { [2^8062 pi] + - 4743158 } - - Its hexadecimal value is: - - FFFFFFFF FFFFFFFF C90FDAA2 2168C234 C4C6628B 80DC1CD1 29024E08 - 8A67CC74 020BBEA6 3B139B22 514A0879 8E3404DD EF9519B3 CD3A431B - 302B0A6D F25F1437 4FE1356D 6D51C245 E485B576 625E7EC6 F44C42E9 - A637ED6B 0BFF5CB6 F406B7ED EE386BFB 5A899FA5 AE9F2411 7C4B1FE6 - 49286651 ECE45B3D C2007CB8 A163BF05 98DA4836 1C55D39A 69163FA8 - FD24CF5F 83655D23 DCA3AD96 1C62F356 208552BB 9ED52907 7096966D - 670C354E 4ABC9804 F1746C08 CA18217C 32905E46 2E36CE3B E39E772C - 180E8603 9B2783A2 EC07A28F B5C55DF0 6F4C52C9 DE2BCBF6 95581718 - 3995497C EA956AE5 15D22618 98FA0510 15728E5A 8AAAC42D AD33170D - 04507A33 A85521AB DF1CBA64 ECFB8504 58DBEF0A 8AEA7157 5D060C7D - B3970F85 A6E1E4C7 ABF5AE8C DB0933D7 1E8C94E0 4A25619D CEE3D226 - 1AD2EE6B F12FFA06 D98A0864 D8760273 3EC86A64 521F2B18 177B200C - BBE11757 7A615D6C 770988C0 BAD946E2 08E24FA0 74E5AB31 43DB5BFC - E0FD108E 4B82D120 A9210801 1A723C12 A787E6D7 88719A10 BDBA5B26 - 99C32718 6AF4E23C 1A946834 B6150BDA 2583E9CA 2AD44CE8 DBBBC2DB - 04DE8EF9 2E8EFC14 1FBECAA6 287C5947 4E6BC05D 99B2964F A090C3A2 - 233BA186 515BE7ED 1F612970 CEE2D7AF B81BDD76 2170481C D0069127 - D5B05AA9 93B4EA98 8D8FDDC1 86FFB7DC 90A6C08F 4DF435C9 34028492 - 36C3FAB4 D27C7026 C1D4DCB2 602646DE C9751E76 3DBA37BD F8FF9406 - AD9E530E E5DB382F 413001AE B06A53ED 9027D831 179727B0 865A8918 - DA3EDBEB CF9B14ED 44CE6CBA CED4BB1B DB7F1447 E6CC254B 33205151 - 2BD7AF42 6FB8F401 378CD2BF 5983CA01 C64B92EC F032EA15 D1721D03 - F482D7CE 6E74FEF6 D55E702F 46980C82 B5A84031 900B1C9E 59E7C97F - BEC7E8F3 23A97A7E 36CC88BE 0F1D45B7 FF585AC5 4BD407B2 2B4154AA - CC8F6D7E BF48E1D8 14CC5ED2 0F8037E0 A79715EE F29BE328 06A1D58B - B7C5DA76 F550AA3D 8A1FBFF0 EB19CCB1 A313D55C DA56C9EC 2EF29632 - 387FE8D7 6E3C0468 043E8F66 3F4860EE 12BF2D5B 0B7474D6 E694F91E - 6DBE1159 74A3926F 12FEE5E4 38777CB6 A932DF8C D8BEC4D0 73B931BA - 3BC832B6 8D9DD300 741FA7BF 8AFC47ED 2576F693 6BA42466 3AAB639C - - - -Taylor, et al. Expires December 15, 2007 [Page 20] - -Internet-Draft Using SRP for TLS Authentication June 2007 - - - 5AE4F568 3423B474 2BF1C978 238F16CB E39D652D E3FDB8BE FC848AD9 - 22222E04 A4037C07 13EB57A8 1A23F0C7 3473FC64 6CEA306B 4BCBC886 - 2F8385DD FA9D4B7F A2C087E8 79683303 ED5BDD3A 062B3CF5 B3A278A6 - 6D2A13F8 3F44F82D DF310EE0 74AB6A36 4597E899 A0255DC1 64F31CC5 - 0846851D F9AB4819 5DED7EA1 B1D510BD 7EE74D73 FAF36BC3 1ECFA268 - 359046F4 EB879F92 4009438B 481C6CD7 889A002E D5EE382B C9190DA6 - FC026E47 9558E447 5677E9AA 9E3050E2 765694DF C81F56E8 80B96E71 - 60C980DD 98EDD3DF FFFFFFFF FFFFFFFF - - - The generator is: 19 (decimal). - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -Taylor, et al. Expires December 15, 2007 [Page 21] - -Internet-Draft Using SRP for TLS Authentication June 2007 - - -Appendix B. SRP Test Vectors - - The following test vectors demonstrate calculation of the verifier - and premaster secret. - - I = "alice" - - P = "password123" - - s = BEB25379 D1A8581E B5A72767 3A2441EE - - N, g = <1024-bit parameters from Appendix A> - - k = 7556AA04 5AEF2CDD 07ABAF0F 665C3E81 8913186F - - x = 94B7555A ABE9127C C58CCF49 93DB6CF8 4D16C124 - - v = - - 7E273DE8 696FFC4F 4E337D05 B4B375BE B0DDE156 9E8FA00A 9886D812 - 9BADA1F1 822223CA 1A605B53 0E379BA4 729FDC59 F105B478 7E5186F5 - C671085A 1447B52A 48CF1970 B4FB6F84 00BBF4CE BFBB1681 52E08AB5 - EA53D15C 1AFF87B2 B9DA6E04 E058AD51 CC72BFC9 033B564E 26480D78 - E955A5E2 9E7AB245 DB2BE315 E2099AFB - - a = - - 60975527 035CF2AD 1989806F 0407210B C81EDC04 E2762A56 AFD529DD - DA2D4393 - - b = - - E487CB59 D31AC550 471E81F0 0F6928E0 1DDA08E9 74A004F4 9E61F5D1 - 05284D20 - - A = - - 61D5E490 F6F1B795 47B0704C 436F523D D0E560F0 C64115BB 72557EC4 - 4352E890 3211C046 92272D8B 2D1A5358 A2CF1B6E 0BFCF99F 921530EC - 8E393561 79EAE45E 42BA92AE ACED8251 71E1E8B9 AF6D9C03 E1327F44 - BE087EF0 6530E69F 66615261 EEF54073 CA11CF58 58F0EDFD FE15EFEA - B349EF5D 76988A36 72FAC47B 0769447B - - B = - - BD0C6151 2C692C0C B6D041FA 01BB152D 4916A1E7 7AF46AE1 05393011 - BAF38964 DC46A067 0DD125B9 5A981652 236F99D9 B681CBF8 7837EC99 - 6C6DA044 53728610 D0C6DDB5 8B318885 D7D82C7F 8DEB75CE 7BD4FBAA - - - -Taylor, et al. Expires December 15, 2007 [Page 22] - -Internet-Draft Using SRP for TLS Authentication June 2007 - - - 37089E6F 9C6059F3 88838E7A 00030B33 1EB76840 910440B1 B27AAEAE - EB4012B7 D7665238 A8E3FB00 4B117B58 - - u = - - CE38B959 3487DA98 554ED47D 70A7AE5F 462EF019 - - <premaster secret> = - - B0DC82BA BCF30674 AE450C02 87745E79 90A3381F 63B387AA F271A10D - 233861E3 59B48220 F7C4693C 9AE12B0A 6F67809F 0876E2D0 13800D6C - 41BB59B6 D5979B5C 00A172B4 A2A5903A 0BDCAF8A 709585EB 2AFAFA8F - 3499B200 210DCC1F 10EB3394 3CD67FC8 8A2F39A4 BE5BEC4E C0A3212D - C346D7E4 74B29EDE 8A469FFE CA686E5A - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -Taylor, et al. Expires December 15, 2007 [Page 23] - -Internet-Draft Using SRP for TLS Authentication June 2007 - - -Appendix C. Acknowledgements - - Thanks to all on the IETF TLS mailing list for ideas and analysis. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -Taylor, et al. Expires December 15, 2007 [Page 24] - -Internet-Draft Using SRP for TLS Authentication June 2007 - - -Authors' Addresses - - David Taylor - Independent - - Email: dtaylor@gnutls.org - - - Tom Wu - Stanford University - - Email: tjw@cs.stanford.edu - - - Nikos Mavrogiannopoulos - Independent - - Email: nmav@gnutls.org - URI: http://www.gnutls.org/ - - - Trevor Perrin - Independent - - Email: trevp@trevp.net - URI: http://trevp.net/ - - - - - - - - - - - - - - - - - - - - - - - - - -Taylor, et al. Expires December 15, 2007 [Page 25] - -Internet-Draft Using SRP for TLS Authentication June 2007 - - -Full Copyright Statement - - Copyright (C) The IETF Trust (2007). - - 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). - - - - - -Taylor, et al. Expires December 15, 2007 [Page 26] - - |