Dogcows Code - chaz/p5-File-KDBX/blob - lib/File/KDBX/Cipher/Stream.pm

   1 package File::KDBX::Cipher::Stream;
   2 # ABSTRACT: A cipher stream encrypter/decrypter
   3
   4 use warnings;
   5 use strict;
   6
   7 use Crypt::Digest qw(digest_data);
   8 use File::KDBX::Constants qw(:cipher :random_stream);
   9 use File::KDBX::Error;
  10 use File::KDBX::Util qw(:class);
  11 use Scalar::Util qw(blessed);
  12 use Module::Load;
  13 use namespace::clean;
  14
  15 extends 'File::KDBX::Cipher';
  16
  17 our $VERSION = '0.900'; # VERSION
  18
  19
  20 has 'counter',  is => 'ro', default => 0;
  21 has 'offset',   is => 'ro';
  22 sub key_size    { { Salsa20 => 32, ChaCha => 32 }->{$_[0]->{algorithm} || ''} //  0 }
  23 sub iv_size     { { Salsa20 =>  8, ChaCha => 12 }->{$_[0]->{algorithm} || ''} // -1 }
  24 sub block_size  { 1 }
  25
  26 sub init {
  27     my $self = shift;
  28     my %args = @_;
  29
  30     if (my $uuid = $args{uuid}) {
  31         if ($uuid eq CIPHER_UUID_CHACHA20 && length($args{iv}) == 16) {
  32             # extract the counter
  33             my $buf = substr($self->{iv}, 0, 4, '');
  34             $self->{counter} = unpack('L<', $buf);
  35         }
  36         elsif ($uuid eq CIPHER_UUID_SALSA20) {
  37             # only need eight bytes...
  38             $self->{iv} = substr($args{iv}, 8);
  39         }
  40     }
  41     elsif (my $id = $args{stream_id}) {
  42         my $key_ref = ref $args{key} ? $args{key} : \$args{key};
  43         if ($id == STREAM_ID_CHACHA20) {
  44             ($self->{key}, $self->{iv}) = unpack('a32 a12', digest_data('SHA512', $$key_ref));
  45         }
  46         elsif ($id == STREAM_ID_SALSA20) {
  47             ($self->{key}, $self->{iv}) = (digest_data('SHA256', $$key_ref), STREAM_SALSA20_IV);
  48         }
  49     }
  50
  51     return $self;
  52 }
  53
  54
  55 sub crypt {
  56     my $self = shift;
  57     my $stream = $self->_stream;
  58     return join('', map { $stream->crypt(ref $_ ? $$_ : $_) } grep { defined } @_);
  59 }
  60
  61
  62 sub keystream {
  63     my $self = shift;
  64     return $self->_stream->keystream(@_);
  65 }
  66
  67
  68 sub dup {
  69     my $self    = shift;
  70     my $class   = blessed($self);
  71
  72     my $dup = bless {%$self, @_}, $class;
  73     delete $dup->{stream};
  74     return $dup;
  75 }
  76
  77 sub _stream {
  78     my $self = shift;
  79
  80     $self->{stream} //= do {
  81         my $s = eval {
  82             my $pkg = 'Crypt::Stream::'.$self->algorithm;
  83             my $counter = $self->counter;
  84             my $pos = 0;
  85             if (defined (my $offset = $self->offset)) {
  86                 $counter = int($offset / 64);
  87                 $pos = $offset % 64;
  88             }
  89             my $s = $pkg->new($self->key, $self->iv, $counter);
  90             # seek to correct position within block
  91             $s->keystream($pos) if $pos;
  92             $s;
  93         };
  94         if (my $err = $@) {
  95             throw 'Failed to initialize stream cipher library',
  96                 error       => $err,
  97                 algorithm   => $self->{algorithm},
  98                 key_length  => length($self->key),
  99                 iv_length   => length($self->iv),
 100                 iv          => unpack('H*', $self->iv),
 101                 key         => unpack('H*', $self->key);
 102         }
 103         $s;
 104     };
 105 }
 106
 107 sub encrypt { goto &crypt }
 108 sub decrypt { goto &crypt }
 109
 110 sub finish { delete $_[0]->{stream}; '' }
 111
 112 1;
 113
 114 __END__
 115
 116 =pod
 117
 118 =encoding UTF-8
 119
 120 =head1 NAME
 121
 122 File::KDBX::Cipher::Stream - A cipher stream encrypter/decrypter
 123
 124 =head1 VERSION
 125
 126 version 0.900
 127
 128 =head1 SYNOPSIS
 129
 130     use File::KDBX::Cipher::Stream;
 131
 132     my $cipher = File::KDBX::Cipher::Stream->new(algorithm => $algorithm, key => $key, iv => $iv);
 133
 134 =head1 DESCRIPTION
 135
 136 A subclass of L<File::KDBX::Cipher> for encrypting and decrypting data using a stream cipher.
 137
 138 =head1 ATTRIBUTES
 139
 140 =head2 counter
 141
 142     $counter = $cipher->counter;
 143
 144 Get the initial counter / block count into the keystream.
 145
 146 =head2 offset
 147
 148     $offset = $cipher->offset;
 149
 150 Get the initial byte offset into the keystream. This has precedence over L</counter> if both are set.
 151
 152 =head1 METHODS
 153
 154 =head2 crypt
 155
 156     $ciphertext = $cipher->crypt($plaintext);
 157     $plaintext = $cipher->crypt($ciphertext);
 158
 159 Encrypt or decrypt some data. These ciphers are symmetric, so encryption and decryption are the same
 160 operation. This method is an alias for both L<File::KDBX::Cipher/encrypt> and L<File::KDBX::Cipher/decrypt>.
 161
 162 =head2 keystream
 163
 164     $stream = $cipher->keystream;
 165
 166 Access the keystream.
 167
 168 =head2 dup
 169
 170     $cipher_copy = $cipher->dup(%attributes);
 171
 172 Get a copy of an existing cipher with the counter reset, optionally applying new attributes.
 173
 174 =head1 BUGS
 175
 176 Please report any bugs or feature requests on the bugtracker website
 177 L<https://github.com/chazmcgarvey/File-KDBX/issues>
 178
 179 When submitting a bug or request, please include a test-file or a
 180 patch to an existing test-file that illustrates the bug or desired
 181 feature.
 182
 183 =head1 AUTHOR
 184
 185 Charles McGarvey <ccm@cpan.org>
 186
 187 =head1 COPYRIGHT AND LICENSE
 188
 189 This software is copyright (c) 2022 by Charles McGarvey.
 190
 191 This is free software; you can redistribute it and/or modify it under
 192 the same terms as the Perl 5 programming language system itself.
 193
 194 =cut