Method setEncryptionMode

/**
 * Sets the AES encryption mode.
 *
 * WARNING: The strength is deprecated as it has a different effect in MCrypt and OpenSSL. MCrypt was abandoned in
 * 2003 before the Rijndael-128 algorithm was officially the Advanced Encryption Standard (AES). MCrypt also offered
 * Rijndael-192 and Rijndael-256 algorithms with different block sizes. These are NOT used in AES. OpenSSL, however,
 * implements AES correctly. It always uses a 128-bit (16 byte) block. The 192 and 256 bit strengths refer to the
 * key size, not the block size. Therefore using different strengths in MCrypt and OpenSSL will result in different
 * and incompatible ciphertexts.
 *
 * TL;DR: Always use $strength = 128!
 *
 * @param   string  $mode      Choose between CBC (recommended) or ECB
 * @param   int     $strength  Bit strength of the key (128, 192 or 256 bits). DEPRECATED. READ NOTES ABOVE.
 *
 * @return  mixed
 */
public function setEncryptionMode($mode = 'cbc', $strength = 128)
{
    static $availableAlgorithms = null;
    static $defaultAlgo = 'aes-128-cbc';
    if (!\is_array($availableAlgorithms)) {
        $availableAlgorithms = openssl_get_cipher_methods();
        foreach (array('aes-256-cbc', 'aes-256-ecb', 'aes-192-cbc', 'aes-192-ecb', 'aes-128-cbc', 'aes-128-ecb') as $algo) {
            if (\in_array($algo, $availableAlgorithms)) {
                $defaultAlgo = $algo;
                break;
            }
        }
    }
    $strength = (int) $strength;
    $mode = strtolower($mode);
    if (!\in_array($strength, array(128, 192, 256))) {
        $strength = 256;
    }
    if (!\in_array($mode, array('cbc', 'ebc'))) {
        $mode = 'cbc';
    }
    $algo = 'aes-' . $strength . '-' . $mode;
    if (!\in_array($algo, $availableAlgorithms)) {
        $algo = $defaultAlgo;
    }
    $this->method = $algo;
}