Commit 127d6cf7 authored by Andy Polyakov's avatar Andy Polyakov
Browse files

crypto/ec/curve25519.c: remove redundant fe[51]_cswap. 



3 least significant bits of the input scalar are explicitly cleared,
hence swap variable has fixed value [of zero] upon exit from the loop.

Reviewed-by: default avatarRich Salz <rsalz@openssl.org>
Reviewed-by: default avatarPaul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/5408)
parent 59bf467c

crypto/ec/curve25519.c

+0 −4
Original line number Diff line number Diff line
@@ -471,8 +471,6 @@ static void x25519_scalar_mult(uint8_t out[32], const uint8_t scalar[32], 
        fe51_mul(z3, x1, z2);

        fe51_mul(z2, tmp1, tmp0);

    }

    fe51_cswap(x2, x3, swap);

    fe51_cswap(z2, z3, swap);



    fe51_invert(z2, z2);

    fe51_mul(x2, x2, z2);
@@ -4050,8 +4048,6 @@ static void x25519_scalar_mult_generic(uint8_t out[32], 
    fe_mul(z3, x1, z2);

    fe_mul(z2, tmp1, tmp0);

  }

  fe_cswap(x2, x3, swap);

  fe_cswap(z2, z3, swap);



  fe_invert(z2, z2);

  fe_mul(x2, x2, z2);