At the end of the post: Update (2013-01-24): Mega has now switched to using SHA-256. They get points for fixing it quickly, but I wonder what other subtle or not-so-subtle security problems remain.

It wouldn't matter. You have no insight in whether Dotcom stores the keys to decrypt the data somewhere. Unless the entire mega fad is open sourced and we can verify the code in the repos runs on their webservers, you cannot justify using Dotcom his bussiness knowing what he has done in the past to obtain financial gain over the backs of others.

It encrypts in the browser, you can check the source code just fine.

The issue with browser-based encryption, is that you would have to check the source code every time that it's served to you.

They could release an api that let you upload with your own client (maybe they have already?)

edit: Apparently there is an API, problem solved.

Not really.

You can verify it once and generate a secure hash from it. Then the second time you could just check the hash.

It wouldn't be too difficult to write a browser extension that did it automatically, or a javascript bookmarklet for it.

But then you have to generate the hash each time the source code changes. And you also have to verify the source code each time yourself because you can't know if it's a regular update from mega (they probably update daily or weekly) or if someone compromised the source code.

That sounds like normal software to me. Nobody is forcing you to update unless the ABI changes. And you can start a mailing list that talks about updates if you like.

You can solve it with something like this: http://perspectives-project.org/

Many sites (like blockchain.info) offer a browser extension which does the checking for you every time automatically. Mega also has a browser extension which does downloading, but I'm unsure if it does checking.

Not really. If enough people audit the code at random times, then the host would not be able to get away with serving malicious code for very long.

In addition to oib pointing out that it was fixed same-day, that security flaw wasn't a big deal in the first place, only relevant if the CDN was compromised.