This is a sample of AES encryption + decryption using CryptoJS. This is a bit different from the examples out there because this one uses a COMPANY header + payload. There's a little bit more processing going on. I also used a CDN for CryptoJS. I hope someone finds this useful.

sample_crypto_aes.js

<script src="https://cdnjs.cloudflare.com/ajax/libs/crypto-js/3.1.2/components/core-min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/crypto-js/3.1.2/components/sha256.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/crypto-js/3.1.2/components/enc-base64.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/crypto-js/3.1.2/rollups/aes.js"></script>
<script>
    function toWordArray(str){
      return CryptoJS.enc.Utf8.parse(str);
    }

    function toString(words){
      return CryptoJS.enc.Utf8.stringify(words);
    }

    function toBase64String(words){
      return CryptoJS.enc.Base64.stringify(words);
    }

    function encrypt(input, key){
  
      var PROTOCOL_AES256 = 2;
      var secret_key = CryptoJS.SHA256(key);
      var header = toWordArray("AMAZON" + String.fromCharCode(PROTOCOL_AES256));
      var iv = CryptoJS.lib.WordArray.random(16);
      var body = CryptoJS.AES.encrypt(json_payload, secret_key, {iv: iv});

      // construct the packet
      // HEADER + IV + BODY
      header.concat(iv);
      header.concat(body.ciphertext);

      // encode in base64
      return toBase64String(header);
    }

    function decrypt(input, key){
      // convert payload encoded in base64 to words
      var packet = CryptoJS.enc.Base64.parse(input);

      // helpers to compute for offsets
      var PROTOCOL_AES256 = 2;
      var secret_key = CryptoJS.SHA256(key);
      var header = toWordArray("AMAZON" + String.fromCharCode(PROTOCOL_AES256));
      var iv = CryptoJS.lib.WordArray.random(16);

      // compute for offsets
      var packet_size = packet.words.length - (iv.words.length + header.words.length);
      var start = iv.words.length + header.words.length;
      var end = packet.words.length;
      
      var ciphertext = CryptoJS.lib.WordArray.create(packet.words.slice(start, end));
      var parsed_iv = CryptoJS.lib.WordArray.create(packet.words.slice(header.words.length, iv.words.length+1));
      ciphertext = toBase64String(ciphertext);
      var decrypted = CryptoJS.AES.decrypt(ciphertext, secret_key, {iv: parsed_iv});

      return toString(decrypted);
    }

    // data
  	var key = "ZxlNEnojO5HbQngiYvrqu32Br6V";
  	var data = {};
    data["name"] = "andrew";
    data["company"] = "amazon";
    var json_payload = JSON.stringify(data);
    
    console.log(json_payload);
    
    var payload = encrypt(json_payload, key);
    var decoded = decrypt(payload, key);

    console.log(decoded);
</script>

Thanks. The one thing I could not get right until I saw your code, was to pass a base64 string to CryptoJS.AES.decrypt().

Thanks for code.
But code is not working. I can see encrypted String but decrypt method return empty string. Please guide

Maybe I'm wrong but on line 24, you are using json_payload instead of input?

Thank you, this just fit like a glove for a setup I'm thinking of.

Maybe I'm wrong but on line 24, you are using json_payload instead of input?

I think this fix is right.