Javascript md5图像哈希与Java进行比较

Question

I am getting a different hash from javascript then I do from java ... I am hoping someone can explain and help to correct this.

The History I am trying to connect to a third party from a mobile app.. I am having to rewrite their java api into javascript which is causing some translation problems. One of the issues is that they are expecting a data array of an image and an md5 hash of that image for comparison. In Java when I use their code I get a different hash to when I do the same thing in javascript.

In java, the code:

byte[] decodedString = Base64.decode(testimg,  Base64.DEFAULT);

MessageDigest md = MessageDigest.getInstance("MD5");
md.reset();
md.update(decodedString);

byte[] array = md.digest();

creates a hash of: ad5e3cdf9174167243ded0e329a37cf6

the same thing in javascript gives: 8bd54f4d1c4800e3df9cdd2aee728ded

var decodedstr = window.atob(testimg);
var hashString = MD5(decodedstr);

In javascript I cannot pass a byte array as with java, but the byte values should be the same (although java displays these as unsigned)

How can I change my image array in javascript to create the same hash and still have a proper image?

Answer 1

Finally got it! Thanks guys for your help and comments. For anyone else who stumbles upon this: Eventually found an MD5 script at: http://blog.faultylabs.com/?d=md5 that will allow me to pass in an arraybuffer and that resolved it.

Or at least, gave me the desired result, Sounds like there is just a lot more trial and error with javascript as everything is handled a bit differently to other languages.

Thanks again.