On Wed, 24 Mar 2004, Alex Bligh wrote:
--On 24 March 2004 10:27 -0800 Tom tom@sdf.com wrote:
DIGEST SIP security. How does this work?
Short answer: almost identically to HTTP authentication. IE a SIP request is sent, server replies with "authentication required" plus a a number (the challenge), the UA responds with a response containing a DIGEST calculation of the number, and the password. The SIP server then compares the digest response with its calculated digest based on the number plus the password. If they are equal, it grants access.
Long answer: read the RFCs
Alex
I think UA auth is well understood due to it similarity to HTTP auth. But how does a SIP server auth itself to a PSTN gateway? Other than host-based security, how does a PSTN gateway know that it is speaking to a trusted SIP server?
RFC3072, which covers a number of auth issues, really deals with the proxy auth, not UA and gateway. RF3329 deals with security between the UA and the first hop SIP entity.
Tom