On Fri, Apr 22, 2022 at 02:40:36AM +0200, Jason A. Donenfeld wrote: > Hi Eric, > > On Thu, Apr 21, 2022 at 05:27:31PM -0700, Eric Biggers wrote: > > +On 64-bit kernels, the hsiphash functions actually implement SipHash-1-3, a > > +reduced-round variant of SipHash, instead of HalfSipHash-1-3. This is because in > > +64-bit code, SipHash-1-3 is no slower than HalfSipHash-1-3, and can be faster. > > +Note, this does *not* mean that in 64-bit kernels the hsiphash functions are the > > +same as the siphash ones, or that they are secure; the hsiphash functions still > > +use an insecure reduced-round algorithm and truncate their outputs to 32 bits. > > Small nit: "less secure" rather than "insecure", as I don't think > there's a super realistic attack against 1-3. I can make that change > when committing if that's fine by you. > > Jason That's fine, assuming that you're just talking about SipHash-1-3, not also HalfSipHash-1-3. The section title is "HalfSipHash - SipHash's insecure younger cousin", so the word "insecure" is applied to HalfSipHash already. - Eric
