Bitcoin Core  24.99.0
P2P Digital Currency
field.h
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1 /***********************************************************************
2  * Copyright (c) 2013, 2014 Pieter Wuille *
3  * Distributed under the MIT software license, see the accompanying *
4  * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
5  ***********************************************************************/
6 
7 #ifndef SECP256K1_FIELD_H
8 #define SECP256K1_FIELD_H
9 
21 #if defined HAVE_CONFIG_H
22 #include "libsecp256k1-config.h"
23 #endif
24 
25 #include "util.h"
26 
27 #if defined(SECP256K1_WIDEMUL_INT128)
28 #include "field_5x52.h"
29 #elif defined(SECP256K1_WIDEMUL_INT64)
30 #include "field_10x26.h"
31 #else
32 #error "Please select wide multiplication implementation"
33 #endif
34 
35 static const secp256k1_fe secp256k1_fe_one = SECP256K1_FE_CONST(0, 0, 0, 0, 0, 0, 0, 1);
37  0x7ae96a2bul, 0x657c0710ul, 0x6e64479eul, 0xac3434e9ul,
38  0x9cf04975ul, 0x12f58995ul, 0xc1396c28ul, 0x719501eeul
39 );
40 
45 
48 
51 
54 
58 
62 static void secp256k1_fe_set_int(secp256k1_fe *r, int a);
63 
66 
68 static int secp256k1_fe_is_zero(const secp256k1_fe *a);
69 
71 static int secp256k1_fe_is_odd(const secp256k1_fe *a);
72 
74 static int secp256k1_fe_equal(const secp256k1_fe *a, const secp256k1_fe *b);
75 
77 static int secp256k1_fe_equal_var(const secp256k1_fe *a, const secp256k1_fe *b);
78 
80 static int secp256k1_fe_cmp_var(const secp256k1_fe *a, const secp256k1_fe *b);
81 
83 static int secp256k1_fe_set_b32(secp256k1_fe *r, const unsigned char *a);
84 
86 static void secp256k1_fe_get_b32(unsigned char *r, const secp256k1_fe *a);
87 
90 static void secp256k1_fe_negate(secp256k1_fe *r, const secp256k1_fe *a, int m);
91 
94 static void secp256k1_fe_mul_int(secp256k1_fe *r, int a);
95 
97 static void secp256k1_fe_add(secp256k1_fe *r, const secp256k1_fe *a);
98 
102 
105 static void secp256k1_fe_sqr(secp256k1_fe *r, const secp256k1_fe *a);
106 
112 static int secp256k1_fe_sqrt(secp256k1_fe *r, const secp256k1_fe *a);
113 
116 static void secp256k1_fe_inv(secp256k1_fe *r, const secp256k1_fe *a);
117 
120 
123 
126 
129 
131 static void secp256k1_fe_cmov(secp256k1_fe *r, const secp256k1_fe *a, int flag);
132 
137 
140 static void secp256k1_fe_get_bounds(secp256k1_fe *r, int m);
141 
142 #endif /* SECP256K1_FIELD_H */
static void secp256k1_fe_inv_var(secp256k1_fe *r, const secp256k1_fe *a)
Potentially faster version of secp256k1_fe_inv, without constant-time guarantee.
static int secp256k1_fe_normalizes_to_zero_var(const secp256k1_fe *r)
Verify whether a field element represents zero i.e.
static void secp256k1_fe_normalize_weak(secp256k1_fe *r)
Weakly normalize a field element: reduce its magnitude to 1, but don't fully normalize.
static int secp256k1_fe_equal_var(const secp256k1_fe *a, const secp256k1_fe *b)
Same as secp256k1_fe_equal, but may be variable time.
static int secp256k1_fe_sqrt(secp256k1_fe *r, const secp256k1_fe *a)
If a has a square root, it is computed in r and 1 is returned.
static void secp256k1_fe_normalize_var(secp256k1_fe *r)
Normalize a field element, without constant-time guarantee.
static void secp256k1_fe_clear(secp256k1_fe *a)
Sets a field element equal to zero, initializing all fields.
static void secp256k1_fe_inv(secp256k1_fe *r, const secp256k1_fe *a)
Sets a field element to be the (modular) inverse of another.
static void secp256k1_fe_cmov(secp256k1_fe *r, const secp256k1_fe *a, int flag)
If flag is true, set *r equal to *a; otherwise leave it.
static void secp256k1_fe_mul_int(secp256k1_fe *r, int a)
Multiplies the passed field element with a small integer constant.
static void secp256k1_fe_negate(secp256k1_fe *r, const secp256k1_fe *a, int m)
Set a field element equal to the additive inverse of another.
static int secp256k1_fe_is_odd(const secp256k1_fe *a)
Check the "oddness" of a field element.
static const secp256k1_fe secp256k1_const_beta
Definition: field.h:36
static void secp256k1_fe_set_int(secp256k1_fe *r, int a)
Set a field element equal to a small (not greater than 0x7FFF), non-negative integer.
static void secp256k1_fe_get_bounds(secp256k1_fe *r, int m)
Sets each limb of 'r' to its upper bound at magnitude 'm'.
static void secp256k1_fe_mul(secp256k1_fe *r, const secp256k1_fe *a, const secp256k1_fe *SECP256K1_RESTRICT b)
Sets a field element to be the product of two others.
static int secp256k1_fe_set_b32(secp256k1_fe *r, const unsigned char *a)
Set a field element equal to 32-byte big endian value.
static int secp256k1_fe_is_zero(const secp256k1_fe *a)
Verify whether a field element is zero.
static void secp256k1_fe_from_storage(secp256k1_fe *r, const secp256k1_fe_storage *a)
Convert a field element back from the storage type.
static void secp256k1_fe_sqr(secp256k1_fe *r, const secp256k1_fe *a)
Sets a field element to be the square of another.
static const secp256k1_fe secp256k1_fe_one
Field element module.
Definition: field.h:35
static int secp256k1_fe_normalizes_to_zero(const secp256k1_fe *r)
Verify whether a field element represents zero i.e.
static void secp256k1_fe_add(secp256k1_fe *r, const secp256k1_fe *a)
Adds a field element to another.
static void secp256k1_fe_normalize(secp256k1_fe *r)
Normalize a field element.
static void secp256k1_fe_half(secp256k1_fe *r)
Halves the value of a field element modulo the field prime.
static void secp256k1_fe_to_storage(secp256k1_fe_storage *r, const secp256k1_fe *a)
Convert a field element to the storage type.
static void secp256k1_fe_get_b32(unsigned char *r, const secp256k1_fe *a)
Convert a field element to a 32-byte big endian value.
static int secp256k1_fe_equal(const secp256k1_fe *a, const secp256k1_fe *b)
Compare two field elements.
static void secp256k1_fe_storage_cmov(secp256k1_fe_storage *r, const secp256k1_fe_storage *a, int flag)
If flag is true, set *r equal to *a; otherwise leave it.
static int secp256k1_fe_cmp_var(const secp256k1_fe *a, const secp256k1_fe *b)
Compare two field elements.
#define SECP256K1_FE_CONST(d7, d6, d5, d4, d3, d2, d1, d0)
Definition: field_10x26.h:40
#define SECP256K1_RESTRICT
Definition: util.h:160