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Differential D9408 Diff 28176 src/secp256k1/src/field_impl.h

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src/secp256k1/src/field_impl.h

/*********************************************************************** /***********************************************************************
* Copyright (c) 2013, 2014 Pieter Wuille * * Copyright (c) 2013, 2014 Pieter Wuille *
* Distributed under the MIT software license, see the accompanying * * Distributed under the MIT software license, see the accompanying *
* file COPYING or https://www.opensource.org/licenses/mit-license.php.* * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
***********************************************************************/ ***********************************************************************/
#ifndef SECP256K1_FIELD_IMPL_H #ifndef SECP256K1_FIELD_IMPL_H
#define SECP256K1_FIELD_IMPL_H #define SECP256K1_FIELD_IMPL_H
#if defined HAVE_CONFIG_H #if defined HAVE_CONFIG_H
#include "libsecp256k1-config.h" #include "libsecp256k1-config.h"
#endif #endif
#include "util.h" #include "util.h"
#include "num.h"
#if defined(SECP256K1_WIDEMUL_INT128) #if defined(SECP256K1_WIDEMUL_INT128)
#include "field_5x52_impl.h" #include "field_5x52_impl.h"
#elif defined(SECP256K1_WIDEMUL_INT64) #elif defined(SECP256K1_WIDEMUL_INT64)
#include "field_10x26_impl.h" #include "field_10x26_impl.h"
#else #else
#error "Please select wide multiplication implementation" #error "Please select wide multiplication implementation"
#endif #endif
▲ Show 20 Lines • Show All 108 Lines • ▼ Show 20 Linesstatic int secp256k1_fe_sqrt(secp256k1_fe *r, const secp256k1_fe *a) {
/* Check that a square root was actually calculated */ /* Check that a square root was actually calculated */
secp256k1_fe_sqr(&t1, r); secp256k1_fe_sqr(&t1, r);
return secp256k1_fe_equal(&t1, a); return secp256k1_fe_equal(&t1, a);
} }
static int secp256k1_fe_is_quad_var(const secp256k1_fe *a) { static int secp256k1_fe_is_quad_var(const secp256k1_fe *a) {
#ifndef USE_NUM_NONE
unsigned char b[32];
secp256k1_num n;
secp256k1_num m;
/* 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
};
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);
return secp256k1_num_jacobi(&n, &m) >= 0;
#else
secp256k1_fe r; secp256k1_fe r;
return secp256k1_fe_sqrt(&r, a); return secp256k1_fe_sqrt(&r, a);
#endif
} }
static const secp256k1_fe secp256k1_fe_one = SECP256K1_FE_CONST(0, 0, 0, 0, 0, 0, 0, 1); static const secp256k1_fe secp256k1_fe_one = SECP256K1_FE_CONST(0, 0, 0, 0, 0, 0, 0, 1);
#endif /* SECP256K1_FIELD_IMPL_H */ #endif /* SECP256K1_FIELD_IMPL_H */