Decrypt Base64 encoded string using PHP

openssl-decrypt.php

<?php

/**
 * Returns the decrypted text.
 *
 * @param $dataToDecrypt
 * @param $key
 *
 * @return false|string
 */
function decrypt($dataToDecrypt, $key) {
  $cipher_algorithm = 'AES-256-CBC';

  $dataToDecrypt = base64_decode($dataToDecrypt);
  $key = base64_decode($key);

  $ivSize = openssl_cipher_iv_length($cipher_algorithm);
  $iv = substr($dataToDecrypt, 0, $ivSize);

  $encData = substr($dataToDecrypt, $ivSize);

  return openssl_decrypt($encData, $cipher_algorithm, $key, OPENSSL_RAW_DATA, $iv);
}

// Example Code
$dataToDecrypt = "5Wqx0pgeh4ST2LLiw1fPmw6VQhqE4Cif1XtILSqSSZM=";
$key = "8QKcoNHVSIfEL0pdT2OkIOM6DB6XpEkjK8mz+VfHR0I=";
$result = decrypt($dataToDecrypt, $key);
print $result; // Output text wil be: 6\LD\%x@Y6