4 ms·
I'm guessing the ransomware uses Salsa10 because it's fast? According to https://www.cryptopp.com/benchmarks.html https://www.cryptopp.com/benchmarks.html, Sal
by Cpoll 11y ago
I'm guessing the ransomware uses Salsa10 because it's fast?
According to https://www.cryptopp.com/benchmarks.html https://www.cryptopp.com/benchmarks.html, Salta20 is 4x faster than AES - and if I understand it, Salsa10 is half the iterations.
- TillE 11y agoSalsa20 / ChaCha20 are quite nice when you want to do byte-for-byte file encryption. It's a good choice in a lot of situations. The unusually reduced number of rounds is more difficult to explain, since I expect hard drive I/O would be the bottleneck in almost any situation. Maybe it's just a little more "stealthy" to not have elevated CPU usage while the ransomware is incubating.
- pbsd 11y agoIt's not Salsa10; it's just that the author is counting double-rounds, which makes it looks like it's half the iterations. This has as many rounds as Salsa20, but whoever converted this to 16-bit words didn't know what they were doing---the security degradation is enormous.
- nightcracker 11y agoEven ChaCha8 (similar to Salsa8) so far is infeasible. The problem is that the randomware used a modified Salsa algorithm that uses 16-bit words instead of 32-bit words. This demolishes the algorithm, and is not a standard modification.