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‎Autoloader.php

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<?php
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namespace PHPCrypt;
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class Autoloader
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{
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public static function load($class_name)
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{
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if (class_exists($class_name)) {
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return TRUE;
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}
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$file_name = self::convertClassToPath($class_name);
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$include_paths = explode(PATH_SEPARATOR, get_include_path());
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foreach ($include_paths as $include_path) {
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$full_path = $include_path . DIRECTORY_SEPARATOR . $file_name;
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if (file_exists($full_path)) {
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include_once $file_name;
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return TRUE;
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}
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}
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return FALSE;
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}
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public static function install()
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{
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spl_autoload_register('self::load');
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}
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public static function convertClassToPath($class_name)
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{
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$path = str_replace('_', DIRECTORY_SEPARATOR, $class_name);
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$path = str_replace('\\', DIRECTORY_SEPARATOR, $path);
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$path .= '.php';
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return $path;
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}
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public static function registerIncludePath()
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{
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set_include_path(
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get_include_path() . PATH_SEPARATOR . realpath(dirname(__FILE__) . '/..')
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);
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}
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}

‎Example.php

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<?php // vim:ts=4:sts=4:sw=4:et:
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require_once 'Autoloader.php';
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\PHPCrypt\Autoloader::install();
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\PHPCrypt\Autoloader::registerIncludePath();
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$phpcrypt = new \PHPCrypt\Simple(
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'6zp4y5vnUQpfEroWI6dMq5lC46F5Dmqa4NDcM1W4u2k=',
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'RJikKksPg3UmqgQPXBwCmcSOMHQn0iOtQAFcfRcQOTU='
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);
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$ciphertext = $phpcrypt->encrypt('Foobar');
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printf("Ciphertext: %s\n", $ciphertext);
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$decrypted = $phpcrypt->decrypt($ciphertext);
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printf("Decrypted: %s\n", $decrypted);

‎README

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\PHPCrypt\ Simple Encryption Library For PHP 5.3+
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Version 1.0
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Written by Bryan C. Geraghty
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Introduction
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============
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A fellow programmer/friend whom I know from my local PHP user group was
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tasked with encrypting some data in an application and started searching
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Google for a good solution. After finding something promising, she sent
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what she had found to me asking for a review, knowing that I have a deep
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intrest and some backgroud in cryptography. Upon reviewing the code, I
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found some critical problems. As I wrote my response and explained the
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fixes that would need to be implemented, I realized that these are not
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things that I could expect anyone without some cryptanalysis experience to
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to implement correctly.
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So, I set out to create this libray in which I have made all of the hard
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decisions for you. There are better contructions out there but they come
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with some baggage that is more difficult to handle and so they are not
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really suited for "simple" libraries. In this library's current design,
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all you must do is run a couple of commands to generate a couple of keys
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that will be stuck in your code. Then, you just call the encrypt() and
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decrypt() functions when you need them.
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My goal with this libary is to improve the baseline for encryption in PHP.
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Cryptgraphic Details
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====================
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For most cryptographic functionality, this libary makes use of the Mcrypt
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extension. The extension has been around for over a decade but is not
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include by default on many distributions. If it is not, you will need to
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ensure that you have installed it.
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The cryptographic primitives & practices behind this library are:
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* 256-bit Rijndael block cipher (256-bit key AND block size; not AES compatible)
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* CBC block cipher mode
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* HMAC-SHA-256
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* Encrypt-Then-MAC construction
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* Constant-time MAC comparison
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Example
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=======
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The goal of this libary was secure defaults and simplicity. There are
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five simple steps to follow to encrypt and decrypt data (see the
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Example.php script to see it all in one place):
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1) Find a Linux machine that has been running for more than 15 minutes and
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generate an encryption key with the following command:
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head -c 32 /dev/urandom | base64
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The output will look something like (IT MUST BE UNIQUE!):
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6zp4y5vnUQpfEroWI6dMq5lC46F5Dmqa4NDcM1W4u2k=
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2) Run the command a second time to generate your MAC key:
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> head -c 32 /dev/urandom | base64
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RJikKksPg3UmqgQPXBwCmcSOMHQn0iOtQAFcfRcQOTU=
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3) Given the above inputs, add the following code to your bootstrap:
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require_once 'PHPCrypt/Autoloader.php';
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\PHPCrypt\Autoloader::install();
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$phpcrypt = new \PHPCrypt\Simple(
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'6zp4y5vnUQpfEroWI6dMq5lC46F5Dmqa4NDcM1W4u2k=',
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'RJikKksPg3UmqgQPXBwCmcSOMHQn0iOtQAFcfRcQOTU=',
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);
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4) Call the encrypt() function:
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$ciphertext = $phpcrypt->encrypt('Foobar');
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This will generate output similar to this:
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DrZ/CdwAxdia1eO4A04jptl+hBpT57xI8FOEiNMSZE2ol0Pk1xDN6IY5VYi9s7wY9q6ubboF7lPnyQRTkx8y5w==|floT1+Ha5GHuO36+wie9rcNh+cQjRDJ5+OegF3mToew=
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As you can see, the output is base64 encoded for you and the MAC is
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appended automatically, so you don't have to worry about anything.
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Just feed plaintext in, and encoded & signed ciphertext comes out.
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Also, keep in mind that the IV for each encryption is randomized, so
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encrypting the same value will produce different ciphertexts. The
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encrypt() function accepts an IV as an optional second argument if you
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need to manually control it. Most people should not use it.
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5) Call the decrypt() function:
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$ciphertext = $phpcrypt->decrypt(
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'DrZ/CdwAxdia1eO4A04jptl+hBpT57xI8FOEiNMSZE2ol0Pk1xDN6IY5VYi9s7wY9q6ubboF7lPnyQRTkx8y5w==|floT1+Ha5GHuO36+wie9rcNh+cQjRDJ5+OegF3mToew='
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);
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This will produce the value, 'Foobar'.
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That's it!
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==========
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I this is better than what we have now.

‎Simple.php

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<?php // vim:ts=4:sts=4:sw=4:et:
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/**
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* Simple Encryption Library For PHP 5.3+
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*
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* PHP Version 5.3
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*
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* @category PHP
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* @package PHPCrypt
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* @author Bryan C. Geraghty <[email protected]>
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* @copyright 2013 Bryan C. Geraghty
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* @license http://www.gnu.org/licenses/lgpl-3.0.txt GNU LGPL
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* @link https://github.com/archwisp/PHPCrypt
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*/
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namespace PHPCrypt;
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class Simple
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{
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private $_encryptionAlgorithm = MCRYPT_RIJNDAEL_256;
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private $_mode = MCRYPT_MODE_CBC;
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private $_macAlgorithm = 'sha256';
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private $_macByteCount = 32;
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private $_encryptionKey;
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private $_macKey;
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public function __construct($encryptionKey, $macKey) {
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$this->_encryptionKey = base64_decode($encryptionKey);
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$this->_macKey = base64_decode($macKey);
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}
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public function encrypt($plaintext, $iv = null) {
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if (is_null($iv)) {
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$iv = $this->generateIv();
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}
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$decodedIv = base64_decode($iv);
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$paddedPlaintext = $this->padWithPkcs7($plaintext);
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$ciphertext = $decodedIv . mcrypt_encrypt($this->_encryptionAlgorithm,
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$this->_encryptionKey, $paddedPlaintext, $this->_mode, $decodedIv
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);
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$signature = hash_hmac($this->_macAlgorithm, $ciphertext, $this->_macKey, true);
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$output = base64_encode($ciphertext) . '|' . base64_encode($signature);
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return $output;
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}
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public function decrypt($signedCiphertext) {
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$signedCiphertextParts = explode('|', $signedCiphertext);
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If (count($signedCiphertextParts) !== 2) {
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Throw new \RuntimeException('Invalid signature');
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}
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$decodedCiphertext = base64_decode($signedCiphertextParts[0]);
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$signature = hash_hmac($this->_macAlgorithm,
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$decodedCiphertext, $this->_macKey, true
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);
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// This should really be a constant-time comparison to prevent timing
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// attacks (see http://blog.jasonmooberry.com/2010/10/constant-time-string-comparison/)
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if (!$this->_compareMac($signature, base64_decode($signedCiphertextParts[1]))) {
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Throw new \RuntimeException('Invalid signature');
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}
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$iv = substr($decodedCiphertext, 0, $this->getBlockSize());
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$ciphertext = substr($decodedCiphertext, $this->getBlockSize());
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$paddedPlaintext = mcrypt_decrypt($this->_encryptionAlgorithm,
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$this->_encryptionKey, $ciphertext, $this->_mode, $iv);
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return $this->trimPkcs7($paddedPlaintext);
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}
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public function generateIv() {
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return base64_encode(mcrypt_create_iv($this->getBlockSize(), MCRYPT_DEV_URANDOM));
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}
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public function generateKey() {
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return base64_encode(mcrypt_create_iv($this->getKeySize(), MCRYPT_DEV_URANDOM));
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}
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private function getBlockSize() {
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return mcrypt_get_iv_size($this->_encryptionAlgorithm, $this->_mode);
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}
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private function getKeySize() {
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return mcrypt_get_key_size($this->_encryptionAlgorithm, $this->_mode);
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}
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private function padWithPkcs7($plaintext) {
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$block_size = $this->getBlockSize();
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if ($block_size > 255) {
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throw new RuntimeException('PKCS7 padding is only well defined for block sizes smaller than 256 bits');
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}
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$pad_length = ($block_size - (strlen($plaintext) % $block_size));
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return $plaintext . str_repeat(chr($pad_length), $pad_length);
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}
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private function trimPkcs7($plaintext) {
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$pad_char = substr($plaintext, -1);
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$pad_length = ord($pad_char);
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if (substr($plaintext, -$pad_length) !== str_repeat($pad_char, $pad_length)) {
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throw new \RuntimeException('Invalid pad value');
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}
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return substr($plaintext, 0, -$pad_length);
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}
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/**
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* Constant-time comparison function
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*
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* Stolen and adapted from:
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* https://cryptocoding.net/index.php/Coding_rules#Compare_secret_strings_in_constant_time
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*
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* DON'T MESS WITH THIS FUNCTION
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*
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* returns boolean true on match, otherwise, false
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*/
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private function _compareMac($a, $b) {
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$result = "\x00";
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for ($i = 0; $i < $this->_macByteCount; $i++) {
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$result |= substr($a, $i, 1) ^ substr($b, $i, 1);
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}
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/* \x00 if equal, nonzero otherwise */
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$return = ($result === "\x00") ? true : false;
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return $return;
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}
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}

‎SimpleTest.php

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<?php // vim:ts=4:sts=4:sw=4:et:
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namespace PHPCrypt;
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class SimpleTest extends \PHPUnit_Framework_TestCase
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{
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private $_instance;
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private $_iv = '3e5VO09Oslbw/sskJPdloizTQ/2iz8Icyo+VT3PxYWM=';
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private $_encryptionKey = 'nXA5gXtlOgHgxl6EZTfkfDmIzWaRqxZ1rq7DRNCIQ/Q=';
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private $_macKey = 'K9iPmOMowXUvcQTd7ehfcxvvHd4OtzyztQp+wuQwb6U=';
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public function setUp() {
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$this->_instance = new \PHPCrypt\Simple($this->_encryptionKey, $this->_macKey);
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}
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public function testEncrypt() {
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$ciphertext = $this->_instance->encrypt('FooBar ', 'lAuCU7ft5tnHPKWRjF1IKV4J6V9/eCGQIisHZfuqMtY=');
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$this->assertEquals(
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'lAuCU7ft5tnHPKWRjF1IKV4J6V9/eCGQIisHZfuqMta/3gJg7IhHgxvaUY6isRyPcRq+x/rQfnPxY/A1XqY2nA==|6MBBCKBbYc+aWLpnk1MQVW2jM5Jnz5oHfXnDriyIL9Q=',
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$ciphertext
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);
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}
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public function testDecrypt() {
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$plaintext = $this->_instance->decrypt(
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'lAuCU7ft5tnHPKWRjF1IKV4J6V9/eCGQIisHZfuqMta/3gJg7IhHgxvaUY6isRyPcRq+x/rQfnPxY/A1XqY2nA==|6MBBCKBbYc+aWLpnk1MQVW2jM5Jnz5oHfXnDriyIL9Q='
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);
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$this->assertEquals('FooBar ', $plaintext);
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}
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/**
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/* This function encrypts the same string with randomized IVs and
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/* flips a single bit of the ciphertext
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*/
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public function invalidCiphertextData() {
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$this->setUp();
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$invalidCiphertexts = array();
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for ($x = 0; $x < 100; $x++) {
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$signedCiphertext = $this->_instance->encrypt('Randomize this with new IVs');
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list($encodedCiphertext, $encodedSignature) = explode('|', $signedCiphertext);
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$ciphertext = base64_decode($encodedCiphertext);
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$randomByte = rand(1, strlen($ciphertext));
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$mask = str_repeat("\x00", $randomByte -1) . "\x01" . str_repeat("\x00", strlen($ciphertext) - $randomByte);
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// SANITY CHECK: If this mask is removed, this test should fail every
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// single run because the ciphertext should match.
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$invalidCiphertext = $ciphertext ^ $mask;
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// printf("Ciphertext: %s\n", bin2hex($ciphertext));
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// printf("Mask: %s\n", bin2hex($mask));
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// printf("Invalid Ciphertext: %s\n", bin2hex($invalidCiphertext));
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$encodedInvalidCiphertext = base64_encode($invalidCiphertext);
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$invalidCiphertexts[] = array($encodedInvalidCiphertext . '|' . $encodedSignature);
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}
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return $invalidCiphertexts;
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}
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/**
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* @dataProvider invalidCiphertextData
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*/
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public function testDecryptInvalidCiphertext($signedCiphertext) {
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$this->setExpectedException('Exception', 'Invalid signature');
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$plaintext = $this->_instance->decrypt($signedCiphertext);
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}
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public function testEncryptAndDecrypt() {
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$plaintext = 'Something';
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$ciphertext = $this->_instance->encrypt('Something');
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$this->assertEquals($plaintext, $this->_instance->decrypt($ciphertext));
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}
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public function testEncryptInvalidIvLength() {
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$this->setExpectedException('Exception');
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$ciphertext = $this->_instance->encrypt(
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'FooBar ', $this->_encryptionKey, $this->macKey, 'Short IV');
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$this->assertEquals('This should never execute', base64_encode($ciphertext));
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}
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public function testGenerateIv() {
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$iv = $this->_instance->generateIv();
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$secondIv = $this->_instance->generateIv();
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$this->assertNotEquals($iv, $secondIv);
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}
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}

‎bin/composer.phar

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