AES 128 CBC encription example (PHP)

aes128_example.php

<?php
/**
 * AES 128 CBC encription example
 */

// Must be 64 chars long & valid hexadecimal. Store it some place safe.
$hex_key = "2cc4e0d365011b7d86b235c4e3dddee45ac3a76dca8536fe10d58d1d481d4b8b";

$key = pack('H*', $hex_key);

// Initialization vector
$iv = openssl_random_pseudo_bytes(16);

// Encryption method
$method = 'AES-128-CBC';

// Options, can be OPENSSL_RAW_DATA or OPENSSL_ZERO_PADDING.
$options = OPENSSL_RAW_DATA;

// Data to encrypt
$data = 'Hello, this is very sensitive data.';

// Encryption process
$encrypted = openssl_encrypt($data, $method, $key, $options, $iv);

/**
 * In order to retrieve the data later the initialization vector must be
 * available. Since it is 16 bits long we'll concatenate it with the 
 * data, store it, and split it later before decrypting.
 *
 * Note that the initialization vector can be stored some place else but
 * it **MUST** be available for decryption.
 */

// Initialization vector along with encrypted data ready to be stored
$encrypted = $iv . $encrypted;

// Obtaining initialization vector and encrypted data
$s_iv = substr($encrypted, 0, 16);
$s_encrypted = substr($encrypted, 16);

$decrypted = openssl_decrypt($s_encrypted, $method, $key, $options, $s_iv);
?>