php mcrypt class

demo.php

<?php

include_once 'Mcrypt.php';

$data = 'Encryption testing data';
$mcrypt = new Mcrypt('password');
$encrypted = $mcrypt->encrypt($data);
echo 'Encrypted data: ' . base64_encode($encrypted) . "\n";
echo 'Decrypted data: ' . $mcrypt->decrypt($encrypted) . "\n";

Mcrypt.php

<?php

class Mcrypt
{

    /**
     * @var string Encryption key
     */
    public $key;

    /**
     * @var string mcrypt mode
     */
    protected $mode;

    /**
     * @var resource mcrypt cipher
     */
    protected $cipher;

    /**
     * @param string $key
     */
    public function __construct($key = '', $cipher = MCRYPT_RIJNDAEL_128, $mode = MCRYPT_MODE_CBC)
    {
        if (!mcrypt_get_cipher_name($cipher)) {
            throw new \InvalidArgumentException('Unsupport mcrypt cipher: ' . $cipher);
        }
        
        if (!in_array($mode, mcrypt_list_modes())) {
            throw new \InvalidArgumentException('Unsupport mcrypt mode: ' . $mode);
        }
        
        $this->cipher = $cipher;
        $this->mode = $mode;
        $this->key = $key;
    }

    /**
     * @param $data
     * @return string
     */
    public function encrypt($data)
    {
        $ivSize = mcrypt_get_iv_size($this->cipher, $this->mode);
        $iv = mcrypt_create_iv($ivSize);
        
        $key = substr(
            mhash(MHASH_SHA256, $this->key),
            0,
            mcrypt_get_key_size($this->cipher, $this->mode)
        );
        
        $encrypted = mcrypt_encrypt(
            $this->cipher, 
            $key, 
            $this->pad($data), 
            $this->mode, 
            $iv
        );
        return $iv . $encrypted;
    }

    /**
     * @param $data
     * @return string
     */
    public function decrypt($data)
    {
        $ivSize = mcrypt_get_iv_size($this->cipher, $this->mode);
        if (strlen($data) < $ivSize + 1) {
            throw new \InvalidArgumentException('Decryption data error');
        }
        $iv = substr($data, 0, $ivSize);
        
        $key = substr(
            mhash(MHASH_SHA256, $this->key),
            0,
            mcrypt_get_key_size($this->cipher, $this->mode)
        );
        
        $decryptedData = mcrypt_decrypt(
            $this->cipher, 
            $key, 
            substr($data, $ivSize),
            $this->mode, 
            $iv
        );
        return $this->unpad($decryptedData);
    }

    private function pad($data)
    {
        $blockSize = mcrypt_get_block_size($this->cipher, $this->mode);
        $pad = $blockSize - (strlen($data) % $blockSize);
        return $data . str_repeat(chr($pad), $pad);
    }

    private function unpad($data)
    {
        $pad = ord($data[strlen($data) - 1]);
        return substr($data, 0, -$pad);
    }
}

McryptTest.php

<?php

include_once 'Mcrypt.php';

class McryptTest extends \PHPUnit_Framework_TestCase
{
	public function testEncryptedMessageShouldNotBeEqualToSourceMessage()
	{
		$mcrypt = new Mcrypt('p@55w0rd');
		$data = 'testing data';
		$this->assertNotEquals($data, $mcrypt->encrypt($data));
	}

	/**
	 * @dataProvider inputDataProvider
	 */
	public function testEncryptionShouldNotChangeMessage($data)
	{
		$mcrypt = new Mcrypt('p@55w0rd');
		$this->assertEquals(
            $data, 
            $mcrypt->decrypt(
                $mcrypt->encrypt($data)
            )
        );
	}

	public function inputDataProvider()
	{
		return array_map(
            function ($item) {
                return array($item);
            }, array(
                'testing data',
                ' testing data with spaces ',
                "testing data
                with

                line break \0\0"
            )
        );
	}

	public function testEncryptedMessageIsDifferentForSameInputs()
	{
		$data = 'testing data';

		$mcrypt = new Mcrypt('p@55w0rd');
		$this->assertNotEquals(
            $mcrypt->encrypt($data),
            $mcrypt->encrypt($data)
        );
	}
    
    public function testDecryptWithWrongKey()
    {
        $data = 'testing data';
        $mcrypt = new Mcrypt('p@55w0rd');
        $encryptedData = $mcrypt->encrypt($data);
        $mcrypt->key = 'password';
        $this->assertNotEquals(
            $data,
            $mcrypt->decrypt($encryptedData)
        );
    }
}