Authenticate as \fIUSER\fR.
.IP
When a connection is made the server sends a \fB221\fR response before any
-command is received. As its first field this contains a challenge string
-encoded in hex.
+command is received. This contains an algorithm name and a challenge encoded
+in hex. Currently the algorithm name is omitted if it is "sha1".
.IP
-The \fIRESPONSE\fR consists of the SHA-1 hash of the user's password
+The \fIRESPONSE\fR consists of the selected hash of the user's password
concatenated with the challenge, encoded in hex.
.TP
.B version