Basic PHP Encryption Algorithm

cipher.php

<?php


$toencrypt = 'The Big Blue House';

$key = 'dGVzdCB0ZXN0IHRlc3QgdGVzdA==';

$cipher = 'AES-128-CBC';


$enc_data = encryptthis($toencrypt, $key, $cipher);

var_dump($enc_data);

echo "<br>";

decryptthis($enc_data, $key, $cipher);


function encryptthis($toencrypt, $key, $cipher){
	$ivlen = openssl_cipher_iv_length($cipher);
	$iv = openssl_random_pseudo_bytes($ivlen); 
	$ciphertext_raw = openssl_encrypt($toencrypt, $cipher, $key, $options=OPENSSL_RAW_DATA, $iv);
	$hmac = hash_hmac('sha256', $ciphertext_raw, $key, $as_binary=true);
	$ciphertext = base64_encode( $iv.$hmac.$ciphertext_raw );
	return $ciphertext;
}

function decryptthis($todecrypt, $key, $cipher){
	$c = base64_decode($todecrypt);
	$ivlen = openssl_cipher_iv_length($cipher="AES-128-CBC");
	$iv = substr($c, 0, $ivlen);
	$hmac = substr($c, $ivlen, $sha2len=32);
	$ciphertext_raw = substr($c, $ivlen+$sha2len);
	$original_plaintext = openssl_decrypt($ciphertext_raw, $cipher, $key, $options=OPENSSL_RAW_DATA, $iv);
	$calcmac = hash_hmac('sha256', $ciphertext_raw, $key, $as_binary=true);
	if (hash_equals($hmac, $calcmac))//PHP 5.6+ timing attack safe comparison
	{
		var_dump($original_plaintext."\n");
	}
}



?>