Authen::Bitcard - Bitcard authentication verification


    use CGI;
    use Authen::Bitcard;
    my $q = CGI->new;
    my $bc = Authen::Bitcard->new;
    # send user to $bc->login_url(r => $return_url);
    # when the user comes back, get the user id with:
    my $user = $bc->verify($q) or die $bc->errstr;


Authen::Bitcard is an implementation of verification for signatures generated by Bitcard authentication. For information on the Bitcard protocol and using Bitcard in other applications, see

The module and the protocol are heavily based on Authen::Typekey. (In fact, the Bitcard authentication server also supports the TypeKey API!)



Create a new Authen::Bitcard object.

$bc->token([ $bitcard_token ])

Your Bitcard token, which you passed to Bitcard when creating the original sign-in link.

This must be set before calling verify or login_url (etc).

$bc->bitcard_url( [ $url ])

Get/set the base URL for the Bitcard service. The default URL is The other *_url methods are build based on the bitcard_url value.

$bc->login_url( r => $return_url )

Returns the URL for the user to login. Takes a hash or hash ref with extra parameters to put in the URL. One of them must be the r parameter with the URL the user will get returned to after logging in (or canceling the login).

$bc->logout_url( r => $return_url )

Returns the URL you can send the user if they wish to logout. Also needs the r parameter for the URL the Bitcard server should send the user back to after logging out.

$bc->account_url( r => $return_url )

Returns the URL the user can edit his Bitcard account information at. Also needs the r parameter like login_url and logout_url.

$bc->register_url( r => $return_url )

Returns the URL for a user to register a new Bitcard account. Also needs the r parameter as above.


Get the URL from which the Bitcard public key can be obtained.

$bc->info_required( $string | [ array ref ] )

With info_required you specify what user data you require. The possible fields are "username", "name" and "email" (see verify for more information).

The method takes either a comma seperated string or a reference to an array.

This must be called before login_url.

NOTE: "name" is currently not implemented well in the Bitcard server, so we recommend you require "username", but mark "name" as optional if you want the "display name" of the user returned.

$bc->info_optional( $string | [ array ref ] )

As info_required except the Bitcard server will ask the user to allow the information to be forwarded, but not require it to proceed.

The Bitcard server will always have a confirmed email address on file before letting a user login.


Verify a Bitcard signature based on the other parameters given. The signature and other parameters are found in the $query object, which should be either a hash reference, or any object that supports a param method--for example, a CGI or Apache::Request object.

If the signature is successfully verified, verify returns a reference to a hash containing the following values.

  • id

    The unique user id of the Bitcard user on your site. It's a 128bit number as a 40 byte hex value.

    The id is always returned when the verification was successful (all other user data fields are optional, see info_required and info_optional).

  • username

    The unique username of the Bitcard user.

  • name

    The user's display name.

  • email

    The user's email address.

  • ts

    The timestamp at which the signature was generated, expressed as seconds since the epoch.

If verification is unsuccessful, verify will return undef, and the error message can be found in $bc->errstr.

$bc->key_cache([ $cache ])

Provide a caching mechanism for the public key.

If $cache is a CODE reference, it is treated as a callback that should return the public key. The callback will be passed two arguments: the Authen::TypeKey object, and the URI of the key. It should return a hash reference with the p, g, q, and pub_key keys set to Math::BigInt objects representing the pieces of the DSA public key.

Otherwise, $cache should be the path to a local file where the public key will be cached/mirrored.

If $cache is not set, the key is not cached. By default, no caching occurs.

$bc->skip_expiry_check([ $boolean ])

Get/set a value indicating whether verify should check the expiration date and time in the TypeKey parameters. The default is to check the expiration date and time.

$bc->expires([ $secs ])

Get/set the amount of time at which a Bitcard signature is intended to expire. The default value is 600 seconds, i.e. 10 minutes.

$bc->ua([ $user_agent ])

Get/set the LWP::UserAgent-like object which will be used to retrieve the regkeys from the network. Needs to support mirror and get methods. By default, LWP::UserAgent is used, and this method as a getter returns undef unless the user agent has been previously set.

$bc->version([ $version ])

Get/set the version of the Bitcard protocol to use. The default version is 3.


Authen::Bitcard is free software; you may redistribute it and/or modify it under the same terms as Perl itself.


Except where otherwise noted, Authen::Bitcard is Copyright 2004-2006 Develooper LLC,

Parts are Copyright 2004 Six Apart Ltd,

All rights reserved.

© 2004-2015 Develooper • Ask Bjørn Hansencontact