RFC 2712 (rfc2712) - Page 2 of 7

Addition of Kerberos Cipher Suites to Transport Layer Security (TLS)

RFC 2712       Addition of Kerberos Cipher Suites to TLS   October 1999


   based on an open standard [2] and is the most widely deployed
   symmetric key authentication system.  This document proposes a new
   option for negotiating Kerberos authentication within the TLS
   framework.  This achieves mutual authentication and the establishment
   of a master secret using Kerberos credentials.  The proposed changes
   are minimal and, in fact, no different from adding a new public key
   algorithm to the TLS framework.

3. Kerberos Authentication Option In TLS

   This section describes the addition of the Kerberos authentication
   option to the TLS protocol.  Throughout this document, we refer to
   the basic SSL handshake shown in Figure 1.  For a review of the TLS
   handshake see [1].

  CLIENT                                             SERVER
  ------                                             ------
 ClientHello
                    -------------------------------->
                                                     ServerHello
                                                     Certificate *
                                                     ServerKeyExchange*
                                                     CertificateRequest*
                                                     ServerHelloDone
                    
     |                                               change cipher spec
     |                                               Finished
     |                                                   |
     |                                                   |
 Application Data   Application Data

 FIGURE 1: The TLS protocol.  All messages followed by a star are
           optional.  Note: This figure was taken from an IETF document
           [1].

   The TLS security context is negotiated in the client and server hello
   messages.  For example: TLS_RSA_WITH_RC4_MD5 means the initial
   authentication will be done using the RSA public key algorithm, RC4
   will be used for the session key, and MACs will be based on the MD5
   algorithm.  Thus, to facilitate the Kerberos authentication option,
   we must start by defining new cipher suites including (but not
   limited to):



Medvinsky & Hur             Standards Track