nodejs 解密小程序用户手机号，编码错误

nodejs 解密小程序用户手机号，编码错误 这是我的代码

var CryptoJS = require("crypto-js");
// 用户在支付宝小程序授权手机号后的 response
var data = "M7FoAhJ2EsP39HVwmIFDYOWgOYFL1TS9WA1jMIybU+PI0htDNwqvs1hXP5wKVwj9lMlTaD/Go2xfPVan61NuH8nrvb2kcqO5df4kP4he/6XOaVx4rmIAVwRfTn+K+7y5KTp+UH+bapt8et0ZbIcRcbjPsB2Xxof+01KYbehLBYNEQSSsmILSOJIYpWG8qzRFfleolrqgNed616iJsxc7+Mx6Au26i3PXxcBuKTp+5Ue81rJGyL5NkdB5MxbN2WCiaJAJrZhnfHsBaGXcVX97hpFnKxvSboJ75zeP8N0B6n9d1AbVGhw3+fcxWNCpBpynNBsNCZHJ2KOyYtn9gGOt0A=="

// 支付宝小程序设置的 AES
var aes = 'Lj59Ubk1ZyzlUZGTKgTl6A==';
// Base64  Utf8
var res =  Buffer.from(data,'base64').toString();

var aes1 =  Buffer.from(aes,'base64').toString();

var bytes  = CryptoJS.AES.decrypt(res, aes1);

var plaintext = bytes.toString(CryptoJS.enc.Utf8);
console.log(plaintext,'plaintext');

请问哪里不对呢？