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ECB.pm  view on Meta::CPAN

				# ...check whether it works as expected
				for my $i (0 .. $bs-1)
				{
					my $plain = ' ' x $i;

					my $padded = $padding->($plain, $bs, 'e') || '';
					die "Provided padding method does not pad properly: Expected $bs bytes, got ", length $padded, ".\n"
						unless (length $padded == $bs);

					my $trunc = $padding->($padded, $bs, 'd') || '';
					die "Provided padding method does not truncate properly: Expected '$plain', got '$trunc'.\n"
						unless ($trunc eq $plain);
				}
			}
		}

		$self->{padding} = $padding;
	}

	return $self->{padding};
}

#
# sets and loads crypting module if argument given
#
sub cipher (\$;$)
{
	my $self = shift;

	if (my $cipher = shift)
	{
		my $module;

		# if a cipher object is provided...
		if (ref $cipher)
		{
			# ...use it
			$self->{_cipherobj} = $cipher;

			$module = ref $cipher;
			($cipher = $module) =~ s/^Crypt:://;
		}

		# else try to load the specified cipher module
		else
		{
			# for compatibility with Crypt::CBC, cipher modules can be specified
			# with or without the 'Crypt::' in front
			$module = $cipher=~/^Crypt/ ? $cipher : "Crypt::$cipher";

			eval "require $module";
			die "Couldn't load $module: $@"."Are you sure '$cipher' is correct? If so,"
			  . " install $module in the proper path or choose some other cipher.\n"
				if $@;

			# delete possibly existing cipher obj from a previous crypt process
			# otherwise changes in the cipher would not be recognized by start()
			$self->{_cipherobj} = '';
		}

		# some packages like Crypt::DES and Crypt::IDEA behave strange in the way
		# that their methods do not belong to the Crypt::DES or Crypt::IDEA namespace
		# but only DES or IDEA instead
		unless ($module->can('blocksize')) { $module=$cipher }

		die "Can't work because Crypt::$cipher doesn't report blocksize."
		  . " Are you sure $cipher is a valid cipher module?\n"
			unless ($module->can('blocksize') && $module->blocksize);

		$self->{blocksize} = $module->blocksize;

		# In opposition to the blocksize, the keysize need not be known by me,
		# but by the one who provides the key. This is because some modules
		# (e.g. Crypt::Blowfish) report keysize 0; in other cases several keysizes
		# are admitted, so reporting just one number would anyway be to narrow
		$self->{keysize} = $module->can('keysize') ? $module->keysize : '';

		$self->{module} = $module;
		$self->{cipher} = $cipher;
	}

	return $self->{cipher};
}


########################################
# public methods - en-/decryption
########################################

#
# sets mode if argument given, either en- or decrypt
# checks, whether all required vars are set
# returns mode
#
sub start (\$$)
{
	my $self = shift;
	my $mode = shift;

	die "Not yet finished existing crypting process. Call finish() before calling start() anew.\n"
		if $self->{_buffer};

	die "Mode has to be either (e)ncrypt or (d)ecrypt.\n"
		unless ($mode=~/^[de]/i);

	# unless a cipher object is provided (see cipher())...
	unless ($self->{_cipherobj})
	{
		# make sure we have a key...
		die "Key not set. Use '\$ecb->key ('some_key'). The key length is probably specified"
		  . " by the algorithm (for example the Crypt::IDEA module needs a sixteen byte key).\n"
			unless $self->{key};

		# ...as well as a block cipher
		die "Can't start() without cipher. Use '\$ecb->cipher(\$cipher)', \$cipher being some"
		  . "  algorithm like for example 'DES', 'IDEA' or 'Blowfish'. Of course, the corresponding"
		  . "  module 'Crypt::\$cipher' needs to be installed.\n"
			unless $self->{module};

		# initialize cipher obj doing the actual en-/decryption
		$self->{_cipherobj} = $self->{module}->new( $self->{key} );
	}

ECB.pm  view on Meta::CPAN

B<encrypt_hex()> and B<decrypt_hex()> are convenience functions
that operate on ciphertext in a hexadecimal representation.
These functions can be useful if, for example, you wish to place
the encrypted information into an e-mail message, web page or URL.

=head1 FUNCTIONS

For convenience en- or decrypting can also be done by calling ordinary
functions. The functions are: B<encrypt()>, B<decrypt()>,
B<encrypt_hex()>, B<decrypt_hex()>.

=head2 encrypt(), decrypt(), encrypt_hex(), decrypt_hex()

  use Crypt::ECB qw(encrypt decrypt encrypt_hex decrypt_hex);

  $ciphertext = encrypt($key, $cipher, $plaintext, $padstyle);
  $plaintext  = decrypt($key, $cipher, $ciphertext, $padstyle);

  $ciphertext = encrypt_hex($key, $cipher, $plaintext, $padstyle);
  $plaintext  = decrypt_hex($key, $cipher, $ciphertext, $padstyle);

B<encrypt()> and B<decrypt()> process the provided text and return either
the corresponding ciphertext (encrypt) or plaintext (decrypt). Data
and padstyle are optional. If the padding style is omitted, 'standard'
is assumed. If data is omitted, $_ is used.

B<encrypt_hex()> and B<decrypt_hex()> operate on ciphertext in a
hexadecimal representation, just like the methods with the same name,
see above. Otherwise usage is the same as for B<encrypt()> and
B<decrypt()>.

=head1 BUGS

None that I know of. Please report if you find any.

=head1 TODO

Implement 'random' padding, see http://www.di-mgt.com.au/cryptopad.html.

A taint check on the key like Crypt::CBC does could be added.

=head1 LICENSE

Crypt-ECB is Copyright (C) 2000, 2005, 2008, 2016 by Christoph Appel.

This module is distributed using the same terms as Perl itself. It is free
software; you can redistribute it and/or modify it under the terms of either:

a) the GNU General Public License as published by the Free Software
Foundation; either version 1, or (at your option) any later version, or

b) the "Artistic License".

=head1 AUTHOR

Christoph Appel (see ECB.pm for email address)

=head1 SEE ALSO

perl(1), Crypt::DES(3), Crypt::IDEA(3), Crypt::CBC(3)

=cut