Hallo Group,

I am playing with the SIP Protocoll. Actually its more UDP, but I did not
see a UDP Newsgroup.
I am writing a C program to operate on the SIP
Protocol. When I try to do a SIP command(REGISER, INVITE) the SIP Server
tells me, that I need to authorize myself. I know the Password, but I am
not able to encrypt it for the protocol. the Sip Proxy wants to know the
Password in DIGEST format and Provides a NONCE Value and wants MD5

Reading the code of softphones I learned about many many different ways
to calculate the digest value, using username,password, uri, realm, nonce,
cnonce, qop, opaque, nc ...
Now I am very confused about all that.
Can anybody tell me the correct formula, which any common sip proxy will
understand ? or maybe redirect me to a better source of information.