libcryptx-perl/lib/Crypt/AuthEnc/OCB.pm
2018-03-22 15:51:09 +01:00

174 lines
4.4 KiB
Perl

package Crypt::AuthEnc::OCB;
use strict;
use warnings;
our $VERSION = '0.048';
use base qw(Crypt::AuthEnc Exporter);
our %EXPORT_TAGS = ( all => [qw( ocb_encrypt_authenticate ocb_decrypt_verify )] );
our @EXPORT_OK = ( @{ $EXPORT_TAGS{'all'} } );
our @EXPORT = qw();
use CryptX;
use Crypt::Cipher;
sub new { my $class = shift; _new(Crypt::Cipher::_trans_cipher_name(shift), @_) }
sub ocb_encrypt_authenticate {
my $cipher_name = shift;
my $key = shift;
my $nonce = shift;
my $adata = shift;
my $plaintext = shift;
my $m = Crypt::AuthEnc::OCB->new($cipher_name, $key, $nonce);
$m->aad_add($adata) if defined $adata;
my $ct = $m->encrypt_last($plaintext);
my $tag = $m->encrypt_done;
return ($ct, $tag);
}
sub ocb_decrypt_verify {
my $cipher_name = shift;
my $key = shift;
my $nonce = shift;
my $adata = shift;
my $ciphertext = shift;
my $tag = shift;
my $m = Crypt::AuthEnc::OCB->new($cipher_name, $key, $nonce);
$m->aad_add($adata) if defined $adata;
my $ct = $m->decrypt_last($ciphertext);
return $m->decrypt_done($tag) ? $ct : undef;
}
sub adata_add {
# obsolete, only for backwards compatibility
shift->aad_add(@_);
}
1;
=pod
=head1 NAME
Crypt::AuthEnc::OCB - Authenticated encryption in OCBv3 mode
=head1 SYNOPSIS
### OO interface
use Crypt::AuthEnc::OCB;
# encrypt and authenticate
my $ae = Crypt::AuthEnc::OCB->new("AES", $key, $nonce);
$ae->aad_add('additional_authenticated_data1');
$ae->aad_add('additional_authenticated_data2');
$ct = $ae->encrypt_add('data1');
$ct = $ae->encrypt_add('data2');
$ct = $ae->encrypt_add('data3');
$ct = $ae->encrypt_last('rest of data');
($ct,$tag) = $ae->encrypt_done();
# decrypt and verify
my $ae = Crypt::AuthEnc::OCB->new("AES", $key, $nonce);
$ae->aad_add('additional_authenticated_data1');
$ae->aad_add('additional_authenticated_data2');
$pt = $ae->decrypt_add('ciphertext1');
$pt = $ae->decrypt_add('ciphertext2');
$pt = $ae->decrypt_add('ciphertext3');
$pt = $ae->decrypt_last('rest of data');
($pt,$tag) = $ae->decrypt_done();
### functional interface
use Crypt::AuthEnc::OCB qw(ocb_encrypt_authenticate ocb_decrypt_verify);
my ($ciphertext, $tag) = ocb_encrypt_authenticate('AES', $key, $nonce, $adata, $plaintext);
my $plaintext = ocb_decrypt_verify('AES', $key, $nonce, $adata, $ciphertext, $tag);
=head1 DESCRIPTION
This module implements OCB version 3 according http://datatracker.ietf.org/doc/draft-irtf-cfrg-ocb/
=head1 EXPORT
Nothing is exported by default.
You can export selected functions:
use Crypt::AuthEnc::OCB qw(ocb_encrypt_authenticate ocb_decrypt_verify);
=head1 FUNCTIONS
=head2 ocb_encrypt_authenticate
my ($ciphertext, $tag) = ocb_encrypt_authenticate($cipher, $key, $nonce, $adata, $plaintext);
# $cipher .. 'AES' or name of any other cipher with 16-byte block len
# $key ..... AES key of proper length (128/192/256bits)
# $nonce ... unique nonce/salt (no need to keep it secret)
# $adata ... additional authenticated data
=head2 ocb_decrypt_verify
my $plaintext = ocb_decrypt_verify($cipher, $key, $nonce, $adata, $ciphertext, $tag);
# on error returns undef
=head1 METHODS
=head2 new
my $ae = Crypt::AuthEnc::OCB->new($cipher, $key, $nonce);
# $cipher .. 'AES' or name of any other cipher with 16-byte block len
# $key ..... AES key of proper length (128/192/256bits)
# $nonce ... unique nonce/salt (no need to keep it secret)
=head2 aad_add
$ae->aad_add($adata); #can be called multiple times
=head2 encrypt_add
$ciphertext = $ae->encrypt_add($data); #can be called multiple times
#BEWARE: size of $data has to be multiple of blocklen (16 for AES)
=head2 encrypt_last
$ciphertext = $ae->encrypt_last($data);
=head2 encrypt_done
$tag = $ae->encrypt_done();
=head2 decrypt_add
$plaintext = $ae->decrypt_add($ciphertext); #can be called multiple times
#BEWARE: size of $ciphertext has to be multiple of blocklen (16 for AES)
=head2 encrypt_last
$plaintext = $ae->decrypt_last($data);
=head2 decrypt_done
my $result = $ae->decrypt_done($tag); # returns 1 (success) or 0 (failure)
#or
my $tag = $ae->decrypt_done; # returns $tag value
=head2 clone
my $ae_new = $ae->clone;
=head1 SEE ALSO
=over
=item * L<CryptX|CryptX>, L<Crypt::AuthEnc::CCM|Crypt::AuthEnc::CCM>, L<Crypt::AuthEnc::GCM|Crypt::AuthEnc::GCM>, L<Crypt::AuthEnc::EAX|Crypt::AuthEnc::EAX>
=item * L<https://en.wikipedia.org/wiki/OCB_mode|https://en.wikipedia.org/wiki/OCB_mode>
=back