TrustPilot Business Generated Links in Node using crypto-js and monotonic-id

TrustPilotLinkBuilder.js

var config                          = require('../config');
var AES                             = require('crypto-js/aes');
var HMAC256                         = require('crypto-js/hmac-sha256');
var Base64                          = require('crypto-js/enc-base64');
var HEX                             = require('crypto-js/enc-hex');
let MID                             = require('monotonic-id');

module.exports = {
    buildData: function(name, email, ref, skus, tags){
        return {
            "email": email,
            "name": name,
            "ref": ref,
            "skus": skus,
            "tags": tags
        }
    },
    buildLink : function (data){
        let encKey = Base64.parse(config.trustpilot.encryptionKey);
        let authKey = Base64.parse(config.trustpilot.authenticationKey);

        let ivString = new MID().toBuffer().toString('hex');

        let iv = HEX.parse(ivString);

        let cipherText = AES.encrypt(JSON.stringify(data), encKey, {iv: iv});

        let ivCipher = iv.concat(cipherText.ciphertext);

        let hmac = HMAC256(ivCipher, authKey);

        let rawPayload = ivCipher.concat(hmac);

        let base64Payload = Base64.stringify(rawPayload);

        let payload = encodeURIComponent(base64Payload);

        return config.trustpilot.baseUrl + config.trustpilot.domain + '?p=' + payload;
    }
};