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package Crypt::DSA::Signature;
use strict;
use Carp qw( croak );
use vars qw{$VERSION};
BEGIN {
$VERSION = '1.16';
}
sub new {
my $class = shift;
my %param = @_;
my $sig = bless { }, $class;
if ($param{Content}) {
return $sig->deserialize(%param);
}
$sig;
}
BEGIN {
no strict 'refs';
for my $meth (qw( r s )) {
*$meth = sub {
my($key, $value) = @_;
if (ref $value eq 'Math::Pari') {
$key->{$meth} = Math::Pari::pari2pv($value);
}
elsif (ref $value) {
$key->{$meth} = "$value";
}
elsif ($value) {
if ($value =~ /^0x/) {
$key->{$meth} = Math::BigInt->new($value)->bstr;
}
else {
$key->{$meth} = $value;
}
}
my $ret = $key->{$meth} || "";
$ret = Math::BigInt->new("$ret") if $ret =~ /^\d+$/;
$ret;
};
}
}
sub asn {
require Convert::ASN1;
my $asn = Convert::ASN1->new;
$asn->prepare('SEQUENCE { r INTEGER, s INTEGER }') or croak $asn->{error};
$asn;
}
sub deserialize {
my $sig = shift;
my %param = @_;
my $asn = __PACKAGE__->asn;
my $ref;
require MIME::Base64;
## Turn off warnings, because we're attempting to base64-decode content
## that may not be base64-encoded.
local $^W = 0;
for ($param{Content}, MIME::Base64::decode_base64($param{Content})) {
my $out = $asn->decode($_);
$ref = $out, last if $out;
}
croak "Invalid Content" unless $ref;
$sig->s($ref->{s});
$sig->r($ref->{r});
$sig;
}
sub serialize {
my $sig = shift;
my %param = @_;
my $asn = __PACKAGE__->asn;
my $buf = $asn->encode({ s => $sig->s, r => $sig->r })
or croak $asn->{error};
$buf;
}
1;
__END__
=head1 NAME
Crypt::DSA::Signature - DSA signature object
=head1 SYNOPSIS
use Crypt::DSA::Signature;
my $sig = Crypt::DSA::Signature->new;
$sig->r($r);
$sig->s($s);
=head1 DESCRIPTION
I<Crypt::DSA::Signature> represents a DSA signature. It has 2 methods,
I<r> and I<s>, which are the big number representations of the 2 pieces of
the DSA signature.
=head1 USAGE
=head2 Crypt::DSA::Signature->new( %options )
Creates a new signature object, and optionally initializes it with the
information in I<%options>, which can contain:
=over 4
=item * Content
An ASN.1-encoded string representing the DSA signature. In ASN.1 notation,
this looks like:
SEQUENCE {
r INTEGER,
s INTEGER
}
If I<Content> is provided, I<new> will automatically call the I<deserialize>
method to parse the content, and set the I<r> and I<s> methods on the
resulting I<Crypt::DSA::Signature> object.
=back
=head2 $sig->serialize
Serializes the signature object I<$sig> into the format described above:
an ASN.1-encoded representation of the signature, using the ASN.1 syntax
above.
=head1 AUTHOR & COPYRIGHTS
Please see the Crypt::DSA manpage for author, copyright,
and license information.
=cut
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