kerberos authentication with SSPI

From: CDA_kerb (CDA_kerb_at_discussions.microsoft.com)
Date: 01/27/05 

Date: Wed, 26 Jan 2005 17:51:02 -0800

I am using SSPI with Kerberos for authentication. The RTC API appears to
authenticate SIP messages with a line in the SIP message:
Authorization: Kerberos - - - gssapi-data=”DATA”, where “DATA” appears to be
the session key.

Using the SSPI calls AcquireCredentialsHandle(), and
InitializeSecurityContext(), I can successfully get data back, but I don’t
know how to extract the “DATA” part out of the buffer for the gssapi-data=
field. Can someone tell me how to extract this out of the buffer that is
returned?