diff --git a/src/ecmult_impl.h b/src/ecmult_impl.h index 490982b27dd06..71ab284741dfc 100644 --- a/src/ecmult_impl.h +++ b/src/ecmult_impl.h @@ -563,15 +563,11 @@ static size_t secp256k1_strauss_max_points(secp256k1_scratch *scratch) { * It has the following guarantees: * - each wnaf[i] is either 0 or an odd integer between -(1 << w) and (1 << w) * - the number of words set is always WNAF_SIZE(w) - * - the returned skew is 0 without endomorphism, or 0 or 1 with endomorphism + * - the returned skew is 0 or 1 */ static int secp256k1_wnaf_fixed(int *wnaf, const secp256k1_scalar *s, int w) { - int sign = 0; int skew = 0; int pos = 1; -#ifndef USE_ENDOMORPHISM - secp256k1_scalar neg_s; -#endif const secp256k1_scalar *work = s; if (secp256k1_scalar_is_zero(s)) { @@ -583,16 +579,10 @@ static int secp256k1_wnaf_fixed(int *wnaf, const secp256k1_scalar *s, int w) { } if (secp256k1_scalar_is_even(s)) { -#ifdef USE_ENDOMORPHISM skew = 1; -#else - secp256k1_scalar_negate(&neg_s, s); - work = &neg_s; - sign = -1; -#endif } - wnaf[0] = (secp256k1_scalar_get_bits_var(work, 0, w) + skew + sign) ^ sign; + wnaf[0] = secp256k1_scalar_get_bits_var(work, 0, w) + skew; while (pos * w < WNAF_BITS) { int now = w; @@ -602,10 +592,10 @@ static int secp256k1_wnaf_fixed(int *wnaf, const secp256k1_scalar *s, int w) { } val = secp256k1_scalar_get_bits_var(work, pos * w, now); if ((val & 1) == 0) { - wnaf[pos - 1] -= ((1 << w) + sign) ^ sign; - wnaf[pos] = (val + 1 + sign) ^ sign; + wnaf[pos - 1] -= (1 << w); + wnaf[pos] = (val + 1); } else { - wnaf[pos] = (val + sign) ^ sign; + wnaf[pos] = val; } /* Set a coefficient to zero if it is 1 or -1 and the proceeding digit * is strictly negative or strictly positive respectively. Only change @@ -678,7 +668,6 @@ static int secp256k1_ecmult_pippenger_wnaf(secp256k1_gej *buckets, int bucket_wi secp256k1_ge tmp; int idx; -#ifdef USE_ENDOMORPHISM if (i == 0) { /* correct for wnaf skew */ int skew = point_state.skew_na; @@ -687,7 +676,6 @@ static int secp256k1_ecmult_pippenger_wnaf(secp256k1_gej *buckets, int bucket_wi secp256k1_gej_add_ge_var(&buckets[0], &buckets[0], &tmp, NULL); } } -#endif if (n > 0) { idx = (n - 1)/2; secp256k1_gej_add_ge_var(&buckets[idx], &buckets[idx], &pt[point_state.input_pos], NULL);