Running window.crypto.getRandomValues() from inside a Web Worker

javascript, web-worker

Solution

There is no way to do this, seeing as the Crypto class and methods are "native code", meaning they are implemented at a lower-level in the browser, so we can't extract the code and move it somewhere else. I tried using Chrome's Transferrable Objects object gets erased from current context and passed to worker, but that throws an error. I don't think that the crypto api needs to be coupled to the DOM ( WebWorkers won't touch the DOM as it isn't thread-safe ), but I've never implemented crypto before. In Node, we have an async api, so to me, at least, it seems like it should be thread-safe.

http://cl.ly/image/0r0P3m3D2h07 <- Inspection of `window.crypto`

http://cl.ly/image/0G1G0F1Y0d3Z <- Example code for passing crypto to WebWorker throws.

I created a WebWorker script to verify, that maybe, just maybe, Chrome and Firefox just had different implementations, and unfortunately, I was mistaken.

I've sent an email to the authors of the W3C Web Crypto API Proposal, and you should as well. The draft seems to have a few open issues at this point, so it seems like it could change. Having either an async API or having the `crypto` API being available in Web Workers seems perfectly reasonable to me. Seems like a bad thing to have blocking the main event loop.

Problem

Original source