File Coverage

blib/lib/Net/SSH/Perl/Cipher/CFB.pm

Criterion	Covered	Total	%
statement	30	30	100.0
branch			n/a
condition	1	3	33.3
subroutine	5	5	100.0
pod	0	3	0.0
total	36	41	87.8

# $Id: CFB.pm,v 1.5 2001/04/03 19:44:47 btrott Exp $

# This code based in part on the Systemics Crypt::CFB.
# Parts Copyright (C) 1995, 1996 Systemics Ltd (http://www.systemics.com/)
# All rights reserved.

package Net::SSH::Perl::Cipher::CFB;
use strict;
use warnings;

sub new {
    my($class, $ciph, $iv) = @_;
    bless {
        cipher    => $ciph,
        iv        => $iv || ("\0" x $ciph->blocksize),
    }, $class;
}

sub encrypt {
    my $cfb = shift;
    my $data = shift;

    my $retval = "";
    my $iv = $cfb->{iv};
    my $size = $cfb->{cipher}->blocksize;

    while (length $data) {
        my $out = $cfb->{cipher}->encrypt($iv);
        $iv = substr($data, 0, $size, '') ^ substr($out, 0, $size, '');
        $retval .= $iv;
    }

    $cfb->{iv} = $iv;
    $retval;
}

sub decrypt {
    my $cfb = shift;
    my $data = shift;

    my $retval = "";
    my $iv = $cfb->{iv};
    my $size = $cfb->{cipher}->blocksize;

    while (length $data) {
        my $out = $cfb->{cipher}->encrypt($iv);
        $iv = substr($data, 0, $size, '');
        $retval .= $iv ^ substr($out, 0, $size);
    }

    $cfb->{iv} = $iv;
    $retval;
}

1;
__END__