view release on metacpan or  search on metacpan

lib/Crypt/RSA/ES/OAEP.pm  view on Meta::CPAN

package Crypt::RSA::ES::OAEP; 
use strict;
use warnings;

## Crypt::RSA::ES::OAEP 
##
## Copyright (c) 2001, Vipul Ved Prakash.  All rights reserved.
## This code is free software; you can redistribute it and/or modify
## it under the same terms as Perl itself.

use base 'Crypt::RSA::Errorhandler';
use Math::Prime::Util  qw/random_bytes/;
use Crypt::RSA::DataFormat qw(bitsize os2ip i2osp octet_xor mgf1 octet_len);
use Crypt::RSA::Primitives;
use Crypt::RSA::Debug      qw(debug);
use Digest::SHA            qw(sha1);
use Sort::Versions         qw(versioncmp);
use Carp;

$Crypt::RSA::ES::OAEP::VERSION = '1.99';

sub new { 
    my ($class, %params) = @_;
    my $self = bless { primitives => new Crypt::RSA::Primitives, 
                       P          => "",
                       hlen       => 20,
                       VERSION    => $Crypt::RSA::ES::OAEP::VERSION,
                      }, $class;
    if ($params{Version}) { 
        if (versioncmp($params{Version}, '1.15') == -1) { 
            $$self{P} = "Crypt::RSA"; 
            $$self{VERSION} = $params{Version};
        } elsif (versioncmp($params{Version}, $$self{VERSION}) == 1) { 
            croak "Required version ($params{Version}) greater than installed version ($$self{VERSION}) of $class.\n";
        }
    }
    return $self;
}


sub encrypt { 
    my ($self, %params) = @_; 
    my $key = $params{Key}; my $M = $params{Message} || $params{Plaintext};
    return $self->error ("Missing Message or Plaintext parameter", \$key, \%params) unless $M;
    return $self->error ($key->errstr, \$M, $key, \%params) unless $key->check;
    my $k = octet_len ($key->n);  debug ("octet_len of modulus: $k");
    my $em = $self->encode ($M, $self->{P}, $k-1) || 
        return $self->error ($self->errstr, \$M, $key, \%params);
    my $m = os2ip ($em);
    my $c = $self->{primitives}->core_encrypt ( Plaintext => $m, Key => $key );
    my $ec = i2osp ($c, $k);  debug ("ec: $ec");
    return $ec;
}    


sub decrypt { 
    my ($self, %params) = @_;
    my $key = $params{Key}; my $C = $params{Cyphertext} || $params{Ciphertext}; 
    return $self->error ("Missing Cyphertext or Ciphertext parameter", \$key, \%params) unless $C;
    return $self->error ($key->errstr, $key, \%params) unless $key->check;
    my $k = octet_len ($key->n);  
    my $c = os2ip ($C);
    if (bitsize($c) > bitsize($key->n)) { 
        return $self->error ("Decryption error.", $key, \%params) 
    }
    my $m = $self->{primitives}->core_decrypt (Cyphertext => $c, Key => $key) || 
        return $self->error ("Decryption error.", $key, \%params);
    my $em = i2osp ($m, $k-1) || 
        return $self->error ("Decryption error.", $key, \%params);
    my $M; $self->errstrrst;  # reset the errstr
    unless ($M = $self->decode ($em, $$self{P})) { 
        return $self->error ("Decryption error.", $key, \%params) if $self->errstr();
        return $M;
    } 
    return $M;
} 


sub encode { 
    my ($self, $M, $P, $emlen) = @_; 
    my $hlen = $$self{hlen};
    my $mlen = length($M);
    return $self->error ("Message too long.", \$P, \$M) if $mlen > $emlen-(2*$hlen)-1;
    my ($PS, $pslen) = ("", 0);