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Comment by tptacek | Hacker News Reader

Generating RSA keys with math.Random is clown crypto, though.

Isn't in-browser crypto clown crypto by definition though?

After all, unless you audit all the code fetched each time you load the page, they can mess with the code client side at any moment without anybody noticing. Is this not more telling about the limits of webdev rather than the skills of Mega's coders?

There are smart people who disagree with me, like Ben Adida at Mozilla, but as a general rule yes, doing crypto inside a browser with Javascript is clownish.

I haven't studied what Mega is doing at all, nor am I ever planning to; my point is just that however badly written the article is, there is indeed evidence that there's bad crypto in this system.

The trust model is inherently broken when doing crypto in the browser the way they are, since the code could be changed at any time. But that doesn't mean you shouldn't implement things properly outside of that.

What do you mean by the code could be changed at any time.

AFAIK this applies to any software.

Every time you visit the website, the crypto code is brand new to you. A site that securely and safely encrypted your data yesterday might be sending keys to the server tomorrow. This is a problem that's fairly unique to doing crypto on the client side in the browser.

That's what Mega seems to be doing in their initAll() function, although since it's being audited with Javascript, it's still insecure.

Is it clown-crypto from the point of view of creating plausible deniability for Mega, or only from the point of view of keeping what your uploading secret from Mega? Genuine question.

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