15

how to do this in Javascript or Jquery?

Please suggest in 2 steps:

1.- Word Array to Single Byte Array.

2.- Byte Array to String.

Maybe this can help:

function hex2a(hex) {
    var str = '';
    for (var i = 0; i < hex.length; i += 2)
        str += String.fromCharCode(parseInt(hex.substr(i, 2), 16));
    return str;
}
4
  • What do you mean by byte array? Commented Aug 9, 2012 at 18:05
  • 1
    First question: why do you need this? There's almost certainly a better way to achieve whatever you're trying to accomplish. Commented Aug 9, 2012 at 18:06
  • @Blazemonger Want to inspect CryptoJS, it gives hashes/cyphers in a Word Array. Commented Aug 9, 2012 at 18:07
  • @Aaron Word Array -> 4 bytes into a single value, Single Byte - > 1 byte into a single value. Commented Aug 9, 2012 at 18:09

1 Answer 1

28

What you are trying to achieve is already implemented in CryptoJS. From the documentation:

You can convert a WordArray object to other formats by explicitly calling the toString method and passing an encoder.

var hash = CryptoJS.SHA256("Message");
alert(hash.toString(CryptoJS.enc.Base64));
alert(hash.toString(CryptoJS.enc.Hex));


Honestly I have no idea why you want to implement that yourself... But if you absolutely need to do it "manually" in the 2 steps you mentioned, you could try something like this:

function wordToByteArray(wordArray) {
    var byteArray = [], word, i, j;
    for (i = 0; i < wordArray.length; ++i) {
        word = wordArray[i];
        for (j = 3; j >= 0; --j) {
            byteArray.push((word >> 8 * j) & 0xFF);
        }
    }
    return byteArray;
}

function byteArrayToString(byteArray) {
    var str = "", i;
    for (i = 0; i < byteArray.length; ++i) {
        str += escape(String.fromCharCode(byteArray[i]));
    }
    return str;
}

var hash = CryptoJS.SHA256("Message");
var byteArray = wordToByteArray(hash.words);
alert(byteArrayToString(byteArray));

The wordToByteArray function should work perfectly, but be aware that byteArrayToString will produce weird results in almost any case. I don't know much about encodings, but ASCII only uses 7 bits so you won't get ASCII chars when trying to encode an entire byte. So I added the escape function to at least be able to display all those strange chars you might get. ;)

I'd recommend you use the functions CryptoJS has already implemented or just use the byte array (without converting it to string) for your analysis.

Sign up to request clarification or add additional context in comments.

Comments

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.