| Current Path : /usr/share/perl5/Crypt/RSA/ |
| Current File : //usr/share/perl5/Crypt/RSA/Key.pm |
#!/usr/bin/perl -sw
##
## Crypt::RSA::Keys
##
## 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.
##
## $Id: Key.pm,v 1.13 2001/05/25 00:20:40 vipul Exp $
package Crypt::RSA::Key;
use strict;
use base 'Class::Loader';
use base 'Crypt::RSA::Errorhandler';
use Crypt::Primes qw(rsaparams);
use Crypt::RSA::DataFormat qw(bitsize);
use Math::Pari qw(PARI Mod lift);
use Crypt::RSA::Key::Private;
use Crypt::RSA::Key::Public;
$Crypt::RSA::Key::VERSION = '1.99';
my %MODMAP = (
Native_PKF => { Module => "Crypt::RSA::Key::Public" },
Native_SKF => { Module => "Crypt::RSA::Key::Private" },
SSH_PKF => { Module => "Crypt::RSA::Key::Public::SSH" },
SSH_SKF => { Module => "Crypt::RSA::Key::Private::SSH" },
);
sub new {
my $class = shift;
my $self = {};
bless $self, $class;
$self->_storemap ( %MODMAP );
return $self;
}
sub generate {
my ($self, %params) = @_;
my $key;
unless ($params{q} && $params{p} && $params{e}) {
return $self->error ("Missing argument.") unless $params{Size};
return $self->error ("Keysize too small.") if
$params{Size} < 48;
return $self->error ("Odd keysize.") if
$params{Size} % 2;
my $size = int($params{Size}/2);
my $verbosity = $params{Verbosity} || 0;
my $cbitsize = 0;
while (!($cbitsize)) {
$key = rsaparams ( Size => $size, Verbosity => $verbosity );
my $n = $$key{p} * $$key{q};
$cbitsize = 1 if bitsize($n) == $params{Size}
}
}
if ($params{KF}) {
$params{PKF} = { Name => "$params{KF}_PKF" };
$params{SKF} = { Name => "$params{KF}_SKF" }
}
my $pubload = $params{PKF} ? $params{PKF} : { Name => "Native_PKF" };
my $priload = $params{SKF} ? $params{SKF} : { Name => "Native_SKF" };
my $pubkey = $self->_load (%$pubload) ||
return $self->error ("Couldn't load the public key module.");
my $prikey = $self->_load ((%$priload), Args => ['Cipher' => $params{Cipher}, 'Password', $params{Password} ]) ||
return $self->error ("Couldn't load the private key module.");
$pubkey->Identity ($params{Identity});
$prikey->Identity ($params{Identity});
$pubkey->e ($$key{e} || $params{e});
$prikey->e ($$key{e} || $params{e});
$prikey->p ($$key{p} || $params{p});
$prikey->q ($$key{q} || $params{q});
$prikey->phi (($prikey->p - 1) * ($prikey->q - 1));
my $m = Mod (1, $prikey->phi);
$prikey->d (lift($m/$pubkey->e));
$prikey->n ($prikey->p * $prikey->q);
$pubkey->n ($prikey->n);
$prikey->dp ($prikey->d % ($prikey->p - 1));
$prikey->dq ($prikey->d % ($prikey->q - 1));
$prikey->u (mod_inverse($prikey->p, $prikey->q));
return $self->error ("d is too small. Regenerate.") if
bitsize($prikey->d) < 0.25 * bitsize($prikey->n);
$$key{p} = 0; $$key{q} = 0; $$key{e} = 0; $m = 0;
if ($params{Filename}) {
$pubkey->write (Filename => "$params{Filename}.public");
$prikey->write (Filename => "$params{Filename}.private");
}
return ($pubkey, $prikey);
}
sub mod_inverse {
my($a, $n) = @_;
my $m = Mod(1, $n);
lift($m / $a);
}
1;
=head1 NAME
Crypt::RSA::Key - RSA Key Pair Generator.
=head1 SYNOPSIS
my $keychain = new Crypt::RSA::Key;
my ($public, $private) = $keychain->generate (
Identity => 'Lord Macbeth <macbeth@glamis.com>',
Size => 2048,
Password => 'A day so foul & fair',
Verbosity => 1,
) or die $keychain->errstr();
=head1 DESCRIPTION
This module provides a method to generate an RSA key pair.
=head1 METHODS
=head2 new()
Constructor.
=head2 generate()
generate() generates an RSA key of specified bitsize. It returns a list of
two elements, a Crypt::RSA::Key::Public object that holds the public part
of the key pair and a Crypt::RSA::Key::Private object that holds that
private part. On failure, it returns undef and sets $self->errstr to
appropriate error string. generate() takes a hash argument with the
following keys:
=over 4
=item B<Size>
Bitsize of the key to be generated. This should be an even integer > 48.
Bitsize is a mandatory argument.
=item B<Password>
String with which the private key will be encrypted. If Password is not
provided the key will be stored unencrypted.
=item B<Identity>
A string that identifies the owner of the key. This string usually takes
the form of a name and an email address. The identity is not bound to the
key with a signature. However, a future release or another module will
provide this facility.
=item B<Cipher>
The block cipher which is used for encrypting the private key. Defaults to
`Blowfish'. Cipher could be set to any value that works with Crypt::CBC(3)
and Tie::EncryptedHash(3).
=item B<Verbosity>
When set to 1, generate() will draw a progress display on STDOUT.
=item B<Filename>
The generated key pair will be written to disk, in $Filename.public and
$Filename.private files, if this argument is provided. Disk writes can be
deferred by skipping this argument and achieved later with the write()
method of Crypt::RSA::Key::Public(3) and Crypt::RSA::Key::Private(3).
=item B<KF>
A string that specifies the key format. As of this writing, two key
formats, `Native' and `SSH', are supported. KF defaults to `Native'.
=item B<SKF>
Secret (Private) Key Format. Instead of specifying KF, the user could
choose to specify secret and public key formats separately. The value for
SKF can be a string ("Native" or "SSH") or a hash reference that specifies
a module name, its constructor and constructor arguments. The specified
module is loaded with Class::Loader(3) and must be interface compatible
with Crypt::RSA::Key::Private(3).
=item B<PKF>
Public Key Format. This option is like SKF but for the public key.
=back
=head1 ERROR HANDLING
See B<ERROR HANDLING> in Crypt::RSA(3) manpage.
=head1 BUGS
There's an inefficiency in the way generate() ensures the key pair is
exactly Size bits long. This will be fixed in a future release.
=head1 AUTHOR
Vipul Ved Prakash, E<lt>mail@vipul.netE<gt>
=head1 SEE ALSO
Crypt::RSA(3), Crypt::RSA::Key::Public(3), Crypt::RSA::Key::Private(3),
Crypt::Primes(3), Tie::EncryptedHash(3), Class::Loader(3)
=cut
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