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ecmult_const: unify endomorphism and non-endomorphism skew cases

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We now do a skew correction even without the endomorphism optimization,
which costs one additional group addition but unifies a lot of code.
This commit is contained in:
Andrew Poelstra
2016-06-30 09:59:10 +00:00
parent b3be8521e6
commit c6191fded8
2 changed files with 25 additions and 52 deletions
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10
src/tests.c
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@@ -2399,9 +2399,7 @@ void test_constant_wnaf(const secp256k1_scalar *number, int w) {
secp256k1_scalar x, shift;
int wnaf[256] = {0};
int i;
#ifdef USE_ENDOMORPHISM
int skew;
#endif
secp256k1_scalar num = *number;
secp256k1_scalar_set_int(&x, 0);
@@ -2411,10 +2409,8 @@ void test_constant_wnaf(const secp256k1_scalar *number, int w) {
for (i = 0; i < 16; ++i) {
secp256k1_scalar_shr_int(&num, 8);
}
skew = secp256k1_wnaf_const(wnaf, num, w);
#else
secp256k1_wnaf_const(wnaf, num, w);
#endif
skew = secp256k1_wnaf_const(wnaf, num, w);
for (i = WNAF_SIZE(w); i >= 0; --i) {
secp256k1_scalar t;
@@ -2433,10 +2429,8 @@ void test_constant_wnaf(const secp256k1_scalar *number, int w) {
}
secp256k1_scalar_add(&x, &x, &t);
}
#ifdef USE_ENDOMORPHISM
/* Skew num because when encoding 128-bit numbers as odd we use an offset */
/* Skew num because when encoding numbers as odd we use an offset */
secp256k1_scalar_cadd_bit(&num, skew == 2, 1);
#endif
CHECK(secp256k1_scalar_eq(&x, &num));
}