Calculate an RFC 2104-compliant HMAC with the SHA256 hash algorithm in ruby

Question

I was going through the Amazon Product Advertising API REST signature docs and I got stuck at #8

Calculate an RFC 2104-compliant HMAC with the SHA256 hash algorithm using the string above with our "dummy" Secret Access Key: 1234567890. For more information about this step, see documentation and code samples for your programming language.

Nevermind, managed to get it on one more try with the help of Calculating a SHA hash with a string + secret key in python. Will post answer below.

Answer 1

You can calculate a keyed-hash message authentication code (HMAC-SHA256) signature with your secret access key by using cryptoJs

First install cryptoJs locally in your system by typing

npm install crypto-js

to install it globally you node a flag -g to the above command. Then add this code and run it.

var CryptoJS = require("crypto-js");

// Calculate an RFC 2104-compliant HMAC with the SHA256 hash algorithm

var exampleString = 
    "GET\n" +
    "webservices.amazon.com\n" +
    "/onca/xml\n" + 
    "AWSAccessKeyId=AKIAIOSFODNN7EXAMPLE&AssociateTag=mytag-20&ItemId=0679722769&Operation=ItemLookup&ResponseGroup=Images%2CItemAttributes%2COffers%2CReviews&Service=AWSECommerceService&Timestamp=2014-08-18T12%3A00%3A00Z&Version=2013-08-01";

var signature = CryptoJS.HmacSHA256(exampleString, "1234567890");

console.log("test signature", signature.toString(CryptoJS.enc.Base64));