AES128 / AES256 CBC with PKCS7Padding in PHP

gistfile1.php

<?

function aes128_cbc_encrypt($key, $data, $iv) {
  if(16 !== strlen($key)) $key = hash('MD5', $key, true);
  if(16 !== strlen($iv)) $iv = hash('MD5', $iv, true);
  $padding = 16 - (strlen($data) % 16);
  $data .= str_repeat(chr($padding), $padding);
  return mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $key, $data, MCRYPT_MODE_CBC, $iv);
}

function aes256_cbc_encrypt($key, $data, $iv) {
  if(32 !== strlen($key)) $key = hash('SHA256', $key, true);
  if(16 !== strlen($iv)) $iv = hash('MD5', $iv, true);
  $padding = 16 - (strlen($data) % 16);
  $data .= str_repeat(chr($padding), $padding);
  return mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $key, $data, MCRYPT_MODE_CBC, $iv);
}

function aes128_cbc_decrypt($key, $data, $iv) {
  if(16 !== strlen($key)) $key = hash('MD5', $key, true);
  if(16 !== strlen($iv)) $iv = hash('MD5', $iv, true);
  $data = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key, $data, MCRYPT_MODE_CBC, $iv);
  $padding = ord($data[strlen($data) - 1]);
  return substr($data, 0, -$padding);
}

function aes256_cbc_decrypt($key, $data, $iv) {
  if(32 !== strlen($key)) $key = hash('SHA256', $key, true);
  if(16 !== strlen($iv)) $iv = hash('MD5', $iv, true);
  $data = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key, $data, MCRYPT_MODE_CBC, $iv);
  $padding = ord($data[strlen($data) - 1]);
  return substr($data, 0, -$padding);
}

I'm not sure if there's another page explaining the context of this gist. For anyone who got here without context (e.g. from Google) - like I did - please note that creating an IV using str_repeat("\0", 16) makes this code absolutely not production-ready! See Block cipher mode of operation at Wikipedia for more details. In short, "In CBC mode, the IV must... be unpredictable at encryption time."

@bojanmartin Yes, you must create it with http://php.net/manual/en/function.mcrypt-create-iv.php

Superb!

Nice ty !

it's deprecated on php 7+