Username of user logging in.
Authentication method used for this request. The default value is "clear", for plain-text authentication. "cookie" and any of the challenge / response methods are also acceptable.
DEPRECATED. Password of user logging in in plaintext. If using the "clear" authentication method, either this or "hpassword" must be present.
DEPRECATED. MD5 digest of user's password. Not much more secure than password, but at least it's not in plain text.
If using challenge / response authentication, this should be the challenge that was issued to you by the server.
If using challenge / response authentication, this should be the response hash that you generate, based on the formula required for your challenge.
Protocol version supported by the client; assumed to be 0 if not specified. See for details on the protocol version