Bitcoin Core  0.19.99
P2P Digital Currency
scalar.h
Go to the documentation of this file.
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 
12 #if defined HAVE_CONFIG_H
13 #include "libsecp256k1-config.h"
14 #endif
15 
16 #if defined(EXHAUSTIVE_TEST_ORDER)
17 #include "scalar_low.h"
18 #elif defined(USE_SCALAR_4X64)
19 #include "scalar_4x64.h"
20 #elif defined(USE_SCALAR_8X32)
21 #include "scalar_8x32.h"
22 #else
23 #error "Please select scalar implementation"
24 #endif
25 
28 
30 static unsigned int secp256k1_scalar_get_bits(const secp256k1_scalar *a, unsigned int offset, unsigned int count);
31 
33 static unsigned int secp256k1_scalar_get_bits_var(const secp256k1_scalar *a, unsigned int offset, unsigned int count);
34 
36 static void secp256k1_scalar_set_b32(secp256k1_scalar *r, const unsigned char *bin, int *overflow);
37 
39 static void secp256k1_scalar_set_int(secp256k1_scalar *r, unsigned int v);
40 
42 static void secp256k1_scalar_get_b32(unsigned char *bin, const secp256k1_scalar* a);
43 
46 
48 static void secp256k1_scalar_cadd_bit(secp256k1_scalar *r, unsigned int bit, int flag);
49 
52 
55 static int secp256k1_scalar_shr_int(secp256k1_scalar *r, int n);
56 
59 
62 
65 
68 
70 static int secp256k1_scalar_is_zero(const secp256k1_scalar *a);
71 
73 static int secp256k1_scalar_is_one(const secp256k1_scalar *a);
74 
76 static int secp256k1_scalar_is_even(const secp256k1_scalar *a);
77 
79 static int secp256k1_scalar_is_high(const secp256k1_scalar *a);
80 
83 static int secp256k1_scalar_cond_negate(secp256k1_scalar *a, int flag);
84 
85 #ifndef USE_NUM_NONE
86 
88 
91 #endif
92 
94 static int secp256k1_scalar_eq(const secp256k1_scalar *a, const secp256k1_scalar *b);
95 
96 #ifdef USE_ENDOMORPHISM
97 
100 static void secp256k1_scalar_split_lambda(secp256k1_scalar *r1, secp256k1_scalar *r2, const secp256k1_scalar *a);
101 #endif
102 
104 static void secp256k1_scalar_mul_shift_var(secp256k1_scalar *r, const secp256k1_scalar *a, const secp256k1_scalar *b, unsigned int shift);
105 
106 #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_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 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.
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 void secp256k1_scalar_split_128(secp256k1_scalar *r1, secp256k1_scalar *r2, const secp256k1_scalar *a)
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:45
static void secp256k1_scalar_order_get_num(secp256k1_num *r)
Get the order of the group as a number.
static int secp256k1_scalar_is_one(const secp256k1_scalar *a)
Check whether a scalar equals one.