> TDL-4's makers created their own encryption algorithm<p>Two comments about this<p>-- I give it maybe a week or two against a good cryptographer. You never, ever invent your own encryption algorithm.<p>-- Even if the encryption algorithm happens to be secure against differential/linear/slide/boomerang attacks, I bet there will be an implementation flaw. It's really hard to get implementation right on those things, even if you have an almost perfect algorithm.<p>Not that that all really matters -- anything that it's encrypted can be decrypted since they key lives on the computer -- but the fact that they created their own encryption algorithm gives some insight in to their minds. Namely, that they they they are smarter than they really are, and that despite all of that, they don't know enough about security to stick with AES.<p>> and the botnet uses the domain names of the C&C servers as the encryption keys.<p>... what? That kind of defeats the entire purpose of encryption when they key is something like that. Besides, what are they using this encryption for. It seems more likely they want a check on the integrity of messages. And even still, a MAC is equally worthless since it's not public/private key.<p>Either (1) this botnet is really weak or (2) the writers of this article have distorted the truth.