# Selima Website Content Management System
# Encrypt.pm: The simple symmetric encrypter/decrypter.

#  Copyright (c) 2004-2018 imacat.
#
#  Licensed under the Apache License, Version 2.0 (the "License");
#  you may not use this file except in compliance with the License.
#  You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
#  Unless required by applicable law or agreed to in writing, software
#  distributed under the License is distributed on an "AS IS" BASIS,
#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#  See the License for the specific language governing permissions and
#  limitations under the License.

# Author: imacat <imacat@mail.imacat.idv.tw>
# First written: 2004-09-26

package Selima::Encrypt;
use 5.008;
use strict;
use warnings;
use base qw(Exporter);
use vars qw(@EXPORT @EXPORT_OK);
BEGIN {
@EXPORT = qw(encrypt decrypt);
@EXPORT_OK = @EXPORT;
# Prototype declaration
sub encrypt($);
sub decrypt($);
}

use Crypt::Rijndael qw();
use MIME::Base64 qw(encode_base64 decode_base64);

use vars qw($cipher);
$cipher = new Crypt::Rijndael(decode_base64("MDkxcTc3dGNvMkRZTTYxM0dqRmZ2R2xvQmNLcUZkNVo="));

# This use symmetric encryption/decryption.  It is not safe.
# Nothing is exported.  Use it by the full package name.

# encrypt: Encrypt
sub encrypt($) {
    local ($_, %_);
    $_ = $_[0];
    $_ = length($_) . " " . $_;
    # Pad with US-ASCII printable characters
    $_ .= chr(32 + int rand 95) while length($_) % 16 != 0;
    return encode_base64($cipher->encrypt($_));
}

# decrypt: Decrypt
sub decrypt($) {
    local ($_, %_);
    $_ = $cipher->decrypt(decode_base64($_[0]));
    s/^(\d+) //;
    return substr $_, 0, $1;
}

return 1;