3 ms·
A proper implementation uses the correct compiler intrinsics and hints to cause such operations to be constant-time. Timing problems are a fairly well-known pro
by cyphar 7y ago
A proper implementation uses the correct compiler intrinsics and hints to cause such operations to be constant-time. Timing problems are a fairly well-known problem in cryptography and constant-time implementations are often required for safe cryptography.
- leni536 7y agoFair enough. I just wanted to point out that standard C is inadequate on its own. I'm pretty sure that cryptographers are aware of this.
- mratsim 7y agoOften that hints boils down to use assembly though. Constant-time is a pain to achieve and new compiler optimizations might make your code not constant-time anymore: https://www.cl.cam.ac.uk/~rja14/Papers/whatyouc.pdf https://www.cl.cam.ac.uk/~rja14/Papers/whatyouc.pdf Given that I'm writing such a cryptographic library, I am very interesting on the compiler hints you use.