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Update Pederson Commitment

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This commit is contained in:
Zhi Guan
2022-11-03 16:48:59 +08:00
parent 9dfc5e5d80
commit 57a3c9682d
4 changed files with 270 additions and 75 deletions
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68
src/sm2_alg.c
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@@ -531,7 +531,7 @@ int sm2_fp_sqrt(SM2_Fp r, const SM2_Fp a)
SM2_BN u;
SM2_BN y; // temp result, prevent call sm2_fp_sqrt(a, a)
// r = a^((p - 1)/4) when p = 3 (mod 4)
// r = a^((p + 1)/4) when p = 3 (mod 4)
sm2_bn_add(u, SM2_P, SM2_ONE);
sm2_bn_rshift(u, u, 2);
sm2_fp_exp(y, a, u);
@@ -1115,6 +1115,30 @@ int sm2_point_from_xy(SM2_POINT *P, const uint8_t x[32], const uint8_t y[32])
return sm2_point_is_on_curve(P);
}
int sm2_point_add(SM2_POINT *R, const SM2_POINT *P, const SM2_POINT *Q)
{
SM2_JACOBIAN_POINT P_;
SM2_JACOBIAN_POINT Q_;
sm2_jacobian_point_from_bytes(&P_, (uint8_t *)P);
sm2_jacobian_point_from_bytes(&Q_, (uint8_t *)Q);
sm2_jacobian_point_add(&P_, &P_, &Q_);
sm2_jacobian_point_to_bytes(&P_, (uint8_t *)R);
return 1;
}
int sm2_point_dbl(SM2_POINT *R, const SM2_POINT *P)
{
SM2_JACOBIAN_POINT P_;
sm2_jacobian_point_from_bytes(&P_, (uint8_t *)P);
sm2_jacobian_point_dbl(&P_, &P_);
sm2_jacobian_point_to_bytes(&P_, (uint8_t *)R);
return 1;
}
int sm2_point_mul(SM2_POINT *R, const uint8_t k[32], const SM2_POINT *P)
{
SM2_BN _k;
@@ -1233,3 +1257,45 @@ int sm2_point_from_der(SM2_POINT *P, const uint8_t **in, size_t *inlen)
}
return 1;
}
int sm2_point_from_hash(SM2_POINT *R, const uint8_t *data, size_t datalen)
{
SM2_BN u;
SM2_Fp x;
SM2_Fp y;
SM2_Fp s;
SM2_Fp s_;
uint8_t dgst[32];
// u = (p + 1)/4
sm2_bn_add(u, SM2_P, SM2_ONE);
sm2_bn_rshift(u, u, 2);
do {
sm3_digest(data, datalen, dgst);
sm2_bn_from_bytes(x, dgst);
if (sm2_bn_cmp(x, SM2_P) >= 0) {
sm2_bn_sub(x, x, SM2_P);
}
// s = y^2 = x^3 + a*x + b
sm2_fp_sqr(s, x);
sm2_fp_sub(s, s, SM2_THREE);
sm2_fp_mul(s, s, x);
sm2_fp_add(s, s, SM2_B);
// y = s^((p+1)/4) = (sqrt(s) (mod p))
sm2_fp_exp(y, s, u);
sm2_fp_sqr(s_, y);
data = dgst;
datalen = sizeof(dgst);
} while (sm2_bn_cmp(s, s_) != 0);
sm2_bn_to_bytes(x, R->x);
sm2_bn_to_bytes(y, R->y);
return 1;
}