php aes-128-cbc

aes-128-cbc.php

<?php

define('ENCRYPTION_KEY', 'EncryptDecryptPHP201908Y');

// Encrypt
function encrypt($plaintext) {
  $ivlen = openssl_cipher_iv_length($cipher = "AES-128-CBC");
  $iv = openssl_random_pseudo_bytes($ivlen);
  $ciphertext_raw = openssl_encrypt($plaintext, $cipher, ENCRYPTION_KEY, $options = OPENSSL_RAW_DATA, $iv);
  $hmac = hash_hmac('sha256', $ciphertext_raw, ENCRYPTION_KEY, $as_binary = true);
  $ciphertext = base64_encode($iv . $hmac . $ciphertext_raw);
  return $ciphertext;
}

// Decrypt
function decrypt($ciphertext) {
  $c = base64_decode($ciphertext);
  $ivlen = openssl_cipher_iv_length($cipher = "AES-128-CBC");
  $iv = substr($c, 0, $ivlen);
  $hmac = substr($c, $ivlen, $sha2len = 32);
  $ciphertext_raw = substr($c, $ivlen + $sha2len);
  $plaintext = openssl_decrypt($ciphertext_raw, $cipher, ENCRYPTION_KEY, $options = OPENSSL_RAW_DATA, $iv);
  $calcmac = hash_hmac('sha256', $ciphertext_raw, ENCRYPTION_KEY, $as_binary = true);
  if (hash_equals($hmac, $calcmac)) {
    return $plaintext;
  }
}