Re: [PATCH v3 01/10] crypto: ecdsa - Convert byte arrays with key coordinates to digits

[Stefan Berger <stefanb@xxxxxxxxxxxxx>]

On 2/29/24 11:48, Lukas Wunner wrote:
> On Thu, Feb 29, 2024 at 09:57:30AM -0500, Stefan Berger wrote:
> > static inline void ecc_digits_from_bytes(const u8 *in, unsigned int nbytes,
> >                                           u64 *out, unsigned int ndigits)
> > {
> >          unsigned int o = nbytes & 7;
> >          u64 msd = 0;
> >          size_t i;
> >
> >          if (o == 0) {
> >                  ecc_swap_digits(in, out, ndigits);
> >          } else {
> >                  for (i = 0; i < o; i++)
> >                          msd = (msd << 8) | in[i];
> >                  out[ndigits - 1] = msd;
> >                  ecc_swap_digits(&in[o], out, ndigits - 1);
> >          }
> > }
>
> Might be beneficial to add a code comment explaining the else-branch
> is for curves with key length not a multiple of 64 bits (such as NIST P521).

Will do. I am also using this here now since it's safer: 
ecc_swap_digits(&in[o], out, (nbytes - o) >> 3);

   Stefan

> Otherwise LGTM, thanks!
>
> Lukas