Is binary hashing possible with CryptoJS?

Question

I want to create an HOTP client using javascript similar to SpeakEasy

The above library is intended for server side javascript usage and it uses NodeJS.

I want to do the same thing on front end javascript in a browser but I haven't been able to use CryptoJS to achieve this behavior.

         var key = "abc";
         var counter = "123";

         // create an octet array from the counter
         var octet_array = new Array(8);

         var counter_temp = counter;

         for (var i = 0; i < 8; i++) {
             var i_from_right = 7 - i;

             // mask 255 over number to get last 8
             octet_array[i_from_right] = counter_temp & 255;

             // shift 8 and get ready to loop over the next batch of 8
             counter_temp = counter_temp >> 8;
         }

        // There is no such class called as Buffer on Browsers (its node js)
         var counter_buffer = new Buffer(octet_array);

         var hash = CryptoJS.HmacSHA1(key,counter_buffer);

         document.write("hex value "+ hash);
         document.write("hash value "+    CryptoJS.enc.Hex.stringify(hash));

I know this is possible on a native platform like java (android) or objective c (ios) Here is the corresponding implementation HOTP in Objective C but I doubt if it's possible to do on a web based front end.

Also, I highly doubt if such a thing is secure in browser because javascript is viewable from any browser. Any inputs suggestions would be useful. I am doing this for a POC. I am curious if anyone has used Hotp on web based platform.

Answer 1

There is no such language that supports binary data strings in the code. You need to encode the binary data into some format such as Hex or Base64 and let CryptoJS decode it into it's own internal binary format which you then can pass to the various CryptoJS functions:

var wordArrayFromUtf = CryptoJS.enc.Utf8.parse("test");
var wordArrayFromHex = CryptoJS.enc.Hex.parse("74657374"); // "test"
var wordArrayFromB64 = CryptoJS.enc.Base64.parse("dGVzdA=="); // "test"

Other functions are:

wordArrayFromHex.toString(CryptoJS.enc.Utf8)  // "test"
CryptoJS.enc.Utf8.stringify(wordArrayFromB64) // "test"

If you pass a string into a CrypoJS function (not these here), it will be assumed to be a Utf8-encoded string. If you don't want that, you need to decode it yourself.