-* user -- user-name of peer
-* remmd -- hash received from peer
-* remmd_len -- length of remmd
-* cstate -- pppd's chap_state structure
+* user -- name of the peer
+* ourname -- name for this machine
+* id -- the ID byte in the challenge
+* digest -- points to the structure representing the digest type
+* challenge -- the challenge string we sent (length in first byte)
+* response -- the response (hash) the peer sent back (length in 1st byte)
+* message -- space for a message to be returned to the peer
+* message_space -- number of bytes available at *message.