Bitcoin Core  0.20.99
P2P Digital Currency
scalar.h
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1 /**********************************************************************
2  * Copyright (c) 2014 Pieter Wuille *
3  * Distributed under the MIT software license, see the accompanying *
4  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
5  **********************************************************************/
6 
7 #ifndef SECP256K1_SCALAR_H
8 #define SECP256K1_SCALAR_H
9 
10 #include "num.h"
11 #include "util.h"
12 
13 #if defined HAVE_CONFIG_H
14 #include "libsecp256k1-config.h"
15 #endif
16 
17 #if defined(EXHAUSTIVE_TEST_ORDER)
18 #include "scalar_low.h"
19 #elif defined(SECP256K1_WIDEMUL_INT128)
20 #include "scalar_4x64.h"
21 #elif defined(SECP256K1_WIDEMUL_INT64)
22 #include "scalar_8x32.h"
23 #else
24 #error "Please select wide multiplication implementation"
25 #endif
26 
29 
31 static unsigned int secp256k1_scalar_get_bits(const secp256k1_scalar *a, unsigned int offset, unsigned int count);
32 
34 static unsigned int secp256k1_scalar_get_bits_var(const secp256k1_scalar *a, unsigned int offset, unsigned int count);
35 
41 static void secp256k1_scalar_set_b32(secp256k1_scalar *r, const unsigned char *bin, int *overflow);
42 
45 static int secp256k1_scalar_set_b32_seckey(secp256k1_scalar *r, const unsigned char *bin);
46 
48 static void secp256k1_scalar_set_int(secp256k1_scalar *r, unsigned int v);
49 
51 static void secp256k1_scalar_get_b32(unsigned char *bin, const secp256k1_scalar* a);
52 
55 
57 static void secp256k1_scalar_cadd_bit(secp256k1_scalar *r, unsigned int bit, int flag);
58 
61 
64 static int secp256k1_scalar_shr_int(secp256k1_scalar *r, int n);
65 
68 
71 
74 
77 
79 static int secp256k1_scalar_is_zero(const secp256k1_scalar *a);
80 
82 static int secp256k1_scalar_is_one(const secp256k1_scalar *a);
83 
85 static int secp256k1_scalar_is_even(const secp256k1_scalar *a);
86 
88 static int secp256k1_scalar_is_high(const secp256k1_scalar *a);
89 
92 static int secp256k1_scalar_cond_negate(secp256k1_scalar *a, int flag);
93 
94 #ifndef USE_NUM_NONE
95 
97 
100 #endif
101 
103 static int secp256k1_scalar_eq(const secp256k1_scalar *a, const secp256k1_scalar *b);
104 
110 
112 static void secp256k1_scalar_mul_shift_var(secp256k1_scalar *r, const secp256k1_scalar *a, const secp256k1_scalar *b, unsigned int shift);
113 
115 static void secp256k1_scalar_cmov(secp256k1_scalar *r, const secp256k1_scalar *a, int flag);
116 
117 #endif /* SECP256K1_SCALAR_H */
static int secp256k1_scalar_eq(const secp256k1_scalar *a, const secp256k1_scalar *b)
Compare two scalars.
static void secp256k1_scalar_mul(secp256k1_scalar *r, const secp256k1_scalar *a, const secp256k1_scalar *b)
Multiply two scalars (modulo the group order).
static int secp256k1_scalar_is_even(const secp256k1_scalar *a)
Check whether a scalar, considered as an nonnegative integer, is even.
static void secp256k1_scalar_get_num(secp256k1_num *r, const secp256k1_scalar *a)
Convert a scalar to a number.
static unsigned int secp256k1_scalar_get_bits(const secp256k1_scalar *a, unsigned int offset, unsigned int count)
Access bits from a scalar.
static void secp256k1_scalar_negate(secp256k1_scalar *r, const secp256k1_scalar *a)
Compute the complement of a scalar (modulo the group order).
static int secp256k1_scalar_is_zero(const secp256k1_scalar *a)
Check whether a scalar equals zero.
static int secp256k1_scalar_shr_int(secp256k1_scalar *r, int n)
Shift a scalar right by some amount strictly between 0 and 16, returning the low bits that were shift...
static void secp256k1_scalar_set_b32(secp256k1_scalar *r, const unsigned char *bin, int *overflow)
Set a scalar from a big endian byte array.
static void secp256k1_scalar_mul_shift_var(secp256k1_scalar *r, const secp256k1_scalar *a, const secp256k1_scalar *b, unsigned int shift)
Multiply a and b (without taking the modulus!), divide by 2**shift, and round to the nearest integer...
static void secp256k1_scalar_split_128(secp256k1_scalar *r1, secp256k1_scalar *r2, const secp256k1_scalar *k)
Find r1 and r2 such that r1+r2*2^128 = k.
static void secp256k1_scalar_inverse(secp256k1_scalar *r, const secp256k1_scalar *a)
Compute the inverse of a scalar (modulo the group order).
static int secp256k1_scalar_is_high(const secp256k1_scalar *a)
Check whether a scalar is higher than the group order divided by 2.
static int secp256k1_scalar_set_b32_seckey(secp256k1_scalar *r, const unsigned char *bin)
Set a scalar from a big endian byte array and returns 1 if it is a valid seckey and 0 otherwise...
static void secp256k1_scalar_sqr(secp256k1_scalar *r, const secp256k1_scalar *a)
Compute the square of a scalar (modulo the group order).
static void secp256k1_scalar_cadd_bit(secp256k1_scalar *r, unsigned int bit, int flag)
Conditionally add a power of two to a scalar.
static void secp256k1_scalar_clear(secp256k1_scalar *r)
Clear a scalar to prevent the leak of sensitive data.
static void secp256k1_scalar_split_lambda(secp256k1_scalar *r1, secp256k1_scalar *r2, const secp256k1_scalar *k)
Find r1 and r2 such that r1+r2*lambda = k, where r1 and r2 or their negations are maximum 128 bits lo...
A scalar modulo the group order of the secp256k1 curve.
Definition: scalar_4x64.h:13
static int secp256k1_scalar_cond_negate(secp256k1_scalar *a, int flag)
Conditionally negate a number, in constant time.
static void secp256k1_scalar_get_b32(unsigned char *bin, const secp256k1_scalar *a)
Convert a scalar to a byte array.
static int secp256k1_scalar_add(secp256k1_scalar *r, const secp256k1_scalar *a, const secp256k1_scalar *b)
Add two scalars together (modulo the group order).
static void secp256k1_scalar_set_int(secp256k1_scalar *r, unsigned int v)
Set a scalar to an unsigned integer.
static void secp256k1_scalar_inverse_var(secp256k1_scalar *r, const secp256k1_scalar *a)
Compute the inverse of a scalar (modulo the group order), without constant-time guarantee.
static unsigned int secp256k1_scalar_get_bits_var(const secp256k1_scalar *a, unsigned int offset, unsigned int count)
Access bits from a scalar.
static int count
Definition: tests.c:35
static void secp256k1_scalar_order_get_num(secp256k1_num *r)
Get the order of the group as a number.
static void secp256k1_scalar_cmov(secp256k1_scalar *r, const secp256k1_scalar *a, int flag)
If flag is true, set *r equal to *a; otherwise leave it.
static int secp256k1_scalar_is_one(const secp256k1_scalar *a)
Check whether a scalar equals one.