NAME

       Authen::SCRAM::Server - RFC 5802 SCRAM Server

VERSION

       version 0.006

SYNOPSIS

           use Authen::SCRAM::Server;
           use Try::Tiny;

           $server = Authen::SCRAM::Server->new(
               credential_cb => \&get_credentials,
           );

           $username = try {
               # get client-first-message

               $server_first = $server->first_msg( $client_first );

               # send to client and get client-final-message

               $server_final = $server->final_msg( $client_final );

               # send to client

               return $server->authorization_id; # returns valid username
           }
           catch {
               die "Authentication failed!"
           };

DESCRIPTION

       This module implements the server-side SCRAM algorithm.

NAME

       Authen::SCRAM::Server - RFC 5802 SCRAM Server

VERSION

       version 0.006

ATTRIBUTES

   credential_cb (required)
       This attribute must contain a code reference that takes a username (as a character string
       normalized by SASLprep) and returns the four user-credential parameters required by SCRAM:
       "salt", "StoredKey", "ServerKey", and "iteration count".  The "salt", "StoredKey" and
       "ServerKey" must be provided as octets (i.e. NOT base64 encoded).

       If the username is unknown, it should return an empty list.

           ($salt, $stored_key, $server_key, $iterations) =
               $server->credential_cb->( $username );

       See RFC 5802: SCRAM Algorithm Overview <http://tools.ietf.org/html/rfc5802#section-3> for
       details.

   auth_proxy_cb
       If provided, this attribute must contain a code reference that takes an authentication
       username and a authorization username (both as character strings), and return a true value
       if the authentication username is permitted to act as the authorization username:

           $bool = $server->auth_proxy_cb->(
               $authentication_user, $authorization_user
           );

       It will only be all called if the authentication username has successfully authenticated.
       Both usernames will have been normalized via "SASLprep" with any transport encoding
       removed before being passed to this function.

   digest
       Name of a digest function available via PBKDF2::Tiny.  Valid values are SHA-1, SHA-224,
       SHA-256, SHA-384, or SHA-512.  Defaults to SHA-1.

   nonce_size
       Size of the client-generated nonce, in bits.  Defaults to 192.  The server-nonce will be
       appended, so the final nonce size will be substantially larger.

   skip_saslprep
       A boolean that defaults to false.  If set to true, usernames and passwords will not be
       normalized through SASLprep.  This is a deviation from the RFC5802 spec and is not
       recommended.

METHODS

   first_msg
           $server_first_msg = $server->first_msg( $client_first_msg );

       This takes the "client-first-message" received from the client and returns the
       "server-first-message" string to be sent to the client to continue a SCRAM session.
       Calling this again will reset the internal state and initiate a new session.  This will
       throw an exception should an error occur.

   final_msg
           $server_final_msg = $server->final_msg( $client_final_msg );

       This takes the "client-final-message" received from the client and returns the
       "server-final-message" string containing the verification signature to be sent to the
       client.

       If an authorization identity was provided by the client, it will confirm that the
       authenticating username is authorized to act as the authorization id using the
       "auth_proxy_cb" attribute.

       If the client credentials do not match or the authentication name is not authorized to act
       as the authorization name, then an exception will be thrown.

   authorization_id
           $username = $client->authorization_id();

       This takes no arguments and returns the authorization identity resulting from the SCRAM
       exchange.  This is the client-supplied authorization identity (if one was provided and
       validated) or else the successfully authenticated identity.

CHARACTER ENCODING CAVEAT

       The SCRAM protocol mandates UTF-8 interchange.  However, all methods in this module take
       and return character strings.  You must encode to UTF-8 before sending and decode from
       UTF-8 on receiving according to whatever transport mechanism you are using.

       This is done to avoid double encoding/decoding problems if your transport is already doing
       UTF-8 encoding or decoding as it constructs outgoing messages or parses incoming messages.

AUTHOR

       David Golden <dagolden@cpan.org>

COPYRIGHT AND LICENSE

       This software is Copyright (c) 2014 by David Golden.

       This is free software, licensed under:

         The Apache License, Version 2.0, January 2004

AUTHOR

       David Golden <dagolden@cpan.org>

COPYRIGHT AND LICENSE

       This software is Copyright (c) 2014 by David Golden.

       This is free software, licensed under:

         The Apache License, Version 2.0, January 2004