Differential D9404 Diff 28171 src/secp256k1/src/field_10x26_impl.h

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src/secp256k1/src/field_10x26_impl.h

Show First 20 Lines • Show All 1,158 Lines • ▼ Show 20 Lines	static SECP256K1_INLINE void secp256k1_fe_from_storage(secp256k1_fe r, const secp256k1_fe_storage a) {
r->n[8] = a->n[6] >> 16 \| ((a->n[7] << 16) & 0x3FFFFFFUL);		r->n[8] = a->n[6] >> 16 \| ((a->n[7] << 16) & 0x3FFFFFFUL);
r->n[9] = a->n[7] >> 10;		r->n[9] = a->n[7] >> 10;
#ifdef VERIFY		#ifdef VERIFY
r->magnitude = 1;		r->magnitude = 1;
r->normalized = 1;		r->normalized = 1;
#endif		#endif
}		}

		static void secp256k1_fe_inv(secp256k1_fe r, const secp256k1_fe a) {
		secp256k1_fe x2, x3, x6, x9, x11, x22, x44, x88, x176, x220, x223, t1;
		int j;

		/** The binary representation of (p - 2) has 5 blocks of 1s, with lengths in
		* { 1, 2, 22, 223 }. Use an addition chain to calculate 2^n - 1 for each block:
		* [1], [2], 3, 6, 9, 11, [22], 44, 88, 176, 220, [223]
		*/

		secp256k1_fe_sqr(&x2, a);
		secp256k1_fe_mul(&x2, &x2, a);

		secp256k1_fe_sqr(&x3, &x2);
		secp256k1_fe_mul(&x3, &x3, a);

		x6 = x3;
		for (j=0; j<3; j++) {
		secp256k1_fe_sqr(&x6, &x6);
		}
		secp256k1_fe_mul(&x6, &x6, &x3);

		x9 = x6;
		for (j=0; j<3; j++) {
		secp256k1_fe_sqr(&x9, &x9);
		}
		secp256k1_fe_mul(&x9, &x9, &x3);

		x11 = x9;
		for (j=0; j<2; j++) {
		secp256k1_fe_sqr(&x11, &x11);
		}
		secp256k1_fe_mul(&x11, &x11, &x2);

		x22 = x11;
		for (j=0; j<11; j++) {
		secp256k1_fe_sqr(&x22, &x22);
		}
		secp256k1_fe_mul(&x22, &x22, &x11);

		x44 = x22;
		for (j=0; j<22; j++) {
		secp256k1_fe_sqr(&x44, &x44);
		}
		secp256k1_fe_mul(&x44, &x44, &x22);

		x88 = x44;
		for (j=0; j<44; j++) {
		secp256k1_fe_sqr(&x88, &x88);
		}
		secp256k1_fe_mul(&x88, &x88, &x44);

		x176 = x88;
		for (j=0; j<88; j++) {
		secp256k1_fe_sqr(&x176, &x176);
		}
		secp256k1_fe_mul(&x176, &x176, &x88);

		x220 = x176;
		for (j=0; j<44; j++) {
		secp256k1_fe_sqr(&x220, &x220);
		}
		secp256k1_fe_mul(&x220, &x220, &x44);

		x223 = x220;
		for (j=0; j<3; j++) {
		secp256k1_fe_sqr(&x223, &x223);
		}
		secp256k1_fe_mul(&x223, &x223, &x3);

		/* The final result is then assembled using a sliding window over the blocks. */

		t1 = x223;
		for (j=0; j<23; j++) {
		secp256k1_fe_sqr(&t1, &t1);
		}
		secp256k1_fe_mul(&t1, &t1, &x22);
		for (j=0; j<5; j++) {
		secp256k1_fe_sqr(&t1, &t1);
		}
		secp256k1_fe_mul(&t1, &t1, a);
		for (j=0; j<3; j++) {
		secp256k1_fe_sqr(&t1, &t1);
		}
		secp256k1_fe_mul(&t1, &t1, &x2);
		for (j=0; j<2; j++) {
		secp256k1_fe_sqr(&t1, &t1);
		}
		secp256k1_fe_mul(r, a, &t1);
		}

		static void secp256k1_fe_inv_var(secp256k1_fe r, const secp256k1_fe a) {
		#if defined(USE_FIELD_INV_BUILTIN)
		secp256k1_fe_inv(r, a);
		#elif defined(USE_FIELD_INV_NUM)
		secp256k1_num n, m;
		static const secp256k1_fe negone = SECP256K1_FE_CONST(
		0xFFFFFFFFUL, 0xFFFFFFFFUL, 0xFFFFFFFFUL, 0xFFFFFFFFUL,
		0xFFFFFFFFUL, 0xFFFFFFFFUL, 0xFFFFFFFEUL, 0xFFFFFC2EUL
		);
		/* secp256k1 field prime, value p defined in "Standards for Efficient Cryptography" (SEC2) 2.7.1. */
		static const unsigned char prime[32] = {
		0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
		0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
		0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
		0xFF,0xFF,0xFF,0xFE,0xFF,0xFF,0xFC,0x2F
		};
		unsigned char b[32];
		int res;
		secp256k1_fe c = *a;
		secp256k1_fe_normalize_var(&c);
		secp256k1_fe_get_b32(b, &c);
		secp256k1_num_set_bin(&n, b, 32);
		secp256k1_num_set_bin(&m, prime, 32);
		secp256k1_num_mod_inverse(&n, &n, &m);
		secp256k1_num_get_bin(b, 32, &n);
		res = secp256k1_fe_set_b32(r, b);
		(void)res;
		VERIFY_CHECK(res);
		/* Verify the result is the (unique) valid inverse using non-GMP code. */
		secp256k1_fe_mul(&c, &c, r);
		secp256k1_fe_add(&c, &negone);
		CHECK(secp256k1_fe_normalizes_to_zero_var(&c));
		#else
		#error "Please select field inverse implementation"
		#endif
		}

#endif /* SECP256K1_FIELD_REPR_IMPL_H */		#endif /* SECP256K1_FIELD_REPR_IMPL_H */