[jdev] What is the purpose of the rspauth?

[LUKE]

I know Step 1.2. is rfc-2831.And i can understand the calculation process.

But  The step 3:  rspauth=ea40f60335c427b5527b84dbabcdfffd

Where the value(ea40f60335c427b5527b84dbabcdfffd) come from?
And what is the purpose of the rspauth. The XMPP document
(http://www.xmpp.org/internet-drafts/draft-saintandre-rfc3920bis-01.html)
does not have any example about rspauth.

=================================================================================
<challenge xmlns='urn:ietf:params:xml:ns:xmpp-sasl'>
cmVhbG09ImV4YW1wbGUuY29tIixub25jZT0iT0E2TUc5dEVRR20yaGgiLHFvcD0i
YXV0aCIsY2hhcnNldD11dGYtOCxhbGdvcml0aG09bWQ1LXNlc3MK
</challenge>

The decoded challenge is:

realm="example.com",nonce="OA6MG9tEQGm2hh",
qop="auth",charset=utf-8,algorithm=md5-sess
================================================================================
<response xmlns='urn:ietf:params:xml:ns:xmpp-sasl'>
dXNlcm5hbWU9Imp1bGlldCIscmVhbG09ImV4YW1wbGUuY29tIixub25jZT0iT0E2
TUc5dEVRR20yaGgiLGNub25jZT0iT0E2TUhYaDZWcVRyUmsiLG5jPTAwMDAwMDAx
LHFvcD1hdXRoLGRpZ2VzdC11cmk9InhtcHAvZXhhbXBsZS5jb20iLHJlc3BvbnNl
PWQzODhkYWQ5MGQ0YmJkNzYwYTE1MjMyMWYyMTQzYWY3LGNoYXJzZXQ9dXRmLTgK
</response>

The decoded response is:
username="juliet",realm="example.com",
nonce="OA6MG9tEQGm2hh",cnonce="OA6MHXh6VqTrRk",
nc=00000001,qop=auth,digest-uri="xmpp/example.com",
response=d388dad90d4bbd760a152321f2143af7,charset=utf-8
=================================================================================
<success xmlns='urn:ietf:params:xml:ns:xmpp-sasl'>
cnNwYXV0aD1lYTQwZjYwMzM1YzQyN2I1NTI3Yjg0ZGJhYmNkZmZmZAo=
</success>

The decoded value for subsequent authentication is:
rspauth=ea40f60335c427b5527b84dbabcdfffd
=================================================================================