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lib/Crypt/RSA/ES/PKCS1v15.pm  view on Meta::CPAN

package Crypt::RSA::ES::PKCS1v15;
use strict;
use warnings;

## Crypt::RSA::ES::PKCS1v15
##
## 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 octet_len os2ip i2osp);
use Crypt::RSA::Primitives;
use Crypt::RSA::Debug      qw(debug);
use Carp;

$Crypt::RSA::ES::PKCS1v15::VERSION = '1.99';

sub new { 
    my ($class, %params) = @_;
    my $self = bless { primitives => new Crypt::RSA::Primitives, 
                       VERSION    => $Crypt::RSA::ES::PKCS1v15::VERSION,
                      }, $class;
    if ($params{Version}) { 
        # do versioning here.
    }
    return $self;
}


sub encrypt { 
    my ($self, %params) = @_; 
    my $key = $params{Key}; my $M = $params{Message} || $params{Plaintext};
    return $self->error ("No 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, $k-1) || 
        return $self->error ($self->errstr, \$M, $key, \%params);
        debug ("encoded: $em");
    my $m = os2ip ($em);
    my $c = $self->{primitives}->core_encrypt (Plaintext => $m, Key => $key);
    my $ec = i2osp ($c, $k);  debug ("cyphertext: $ec");
    return $ec;
}    


sub decrypt { 
    my ($self, %params) = @_;
    my $key = $params{Key}; my $C = $params{Cyphertext} || $params{Ciphertext};
    return $self->error ("No 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);
    debug ("bitsize(c): " . bitsize($c));
    debug ("bitsize(n): " . bitsize($key->n));
    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)) { 
        return $self->error ("Decryption error.", $key, \%params) if $self->errstr();
        return $M;
    } 
    return $M;
} 


sub encode { 
    my ($self, $M, $emlen) = @_; 
    $M = $M || ""; my $mlen = length($M);
    return $self->error ("Message too long.", \$M) if $mlen > $emlen-10;

    my $pslen = $emlen-$mlen-2;
    # my $PS = join('', map { chr( 1+urandomm(255) ) } 1 .. $pslen);
    my $PS = '';
    while (length($PS) < $pslen) {
      $PS .= random_bytes( $pslen - length($PS) );