#!/usr/bin/perl

# Copyright 2005-2006 Messiah College. All rights reserved.
# Jason Long <jlong@messiah.edu>

# Copyright (c) 2004 Anthony D. Urso. All rights reserved.
# This program is free software; you can redistribute it and/or
# modify it under the same terms as Perl itself.

use strict;
use warnings;

package Mail::DKIM::Algorithm::rsa_sha256;
use base 'Mail::DKIM::Algorithm::Base';
use Carp;
use MIME::Base64;
use Digest::SHA;

sub init_digests {
    my $self = shift;

    # initialize a SHA-256 Digest
    $self->{header_digest} = new Digest::SHA(256);
    $self->{body_digest}   = new Digest::SHA(256);
}

sub sign {
    my $self = shift;
    croak 'wrong number of arguments' unless ( @_ == 1 );
    my ($private_key) = @_;

    my $digest = $self->{header_digest}->digest;
    my $signature = $private_key->sign_digest( 'SHA-256', $digest );

    return encode_base64( $signature, '' );
}

sub verify {
    my $self = shift;
    croak 'wrong number of arguments' unless ( @_ == 0 );

    my $base64     = $self->signature->data;
    my $public_key = $self->signature->get_public_key;

    my $digest = $self->{header_digest}->digest;
    my $sig    = decode_base64($base64);
    return unless $public_key->verify_digest( 'SHA-256', $digest, $sig );
    return $self->check_body_hash;
}

sub wants_pre_signature_headers {
    return 1;
}

1;