decrypt.js

var decrypt = function (encrypted, method, secret, hmac) {
  var iv = new Buffer.from(encrypted.substr(0, 24), "base64").toString();
  var decryptor = crypto.createDecipheriv(method, secret, iv);
  return (
    decryptor.update(encrypted.substr(24), "base64", "utf8") +
    decryptor.final("utf8")
  );
};