PHP CBC (Cypher Block Chaining) Encryption

cbc.php

<?php
define('AES_256_CBC', 'aes-256-cbc');

$data = "The string that will be encrypted/decrypted";

$encryption_key = openssl_random_pseudo_bytes(16); // 32 bytes can also be used
$iv = openssl_random_pseudo_bytes(openssl_cipher_iv_length(AES_256_CBC));
$encrypted = openssl_encrypt($data, AES_256_CBC, $encryption_key, 0, $iv);

echo "Encrypted: $encrypted\n";

$encrypted = $encrypted.':'.$iv;
$parts = explode(':', $encrypted);
$decrypted = openssl_decrypt($parts[0], AES_256_CBC, $encryption_key, 0, $parts[1]);

echo "Decrypted: $decrypted\n"