Bitcoin Core  27.99.0 P2P Digital Currency
modinv32.h
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1 /***********************************************************************
2  * Copyright (c) 2020 Peter Dettman *
5  **********************************************************************/
6
7 #ifndef SECP256K1_MODINV32_H
8 #define SECP256K1_MODINV32_H
9
10 #include "util.h"
11
12 /* A signed 30-bit limb representation of integers.
13  *
14  * Its value is sum(v[i] * 2^(30*i), i=0..8). */
15 typedef struct {
16  int32_t v[9];
18
19 typedef struct {
20  /* The modulus in signed30 notation, must be odd and in [3, 2^256]. */
22
23  /* modulus^{-1} mod 2^30 */
24  uint32_t modulus_inv30;
26
27 /* Replace x with its modular inverse mod modinfo->modulus. x must be in range [0, modulus).
28  * If x is zero, the result will be zero as well. If not, the inverse must exist (i.e., the gcd of
29  * x and modulus must be 1). These rules are automatically satisfied if the modulus is prime.
30  *
31  * On output, all of x's limbs will be in [0, 2^30).
32  */
34
35 /* Same as secp256k1_modinv32_var, but constant time in x (not in the modulus). */
37
38 /* Compute the Jacobi symbol for (x | modinfo->modulus). x must be coprime with modulus (and thus
39  * cannot be 0, as modulus >= 3). All limbs of x must be non-negative. Returns 0 if the result
40  * cannot be computed. */
42
43 #endif /* SECP256K1_MODINV32_H */
static void secp256k1_modinv32_var(secp256k1_modinv32_signed30 *x, const secp256k1_modinv32_modinfo *modinfo)
static void secp256k1_modinv32(secp256k1_modinv32_signed30 *x, const secp256k1_modinv32_modinfo *modinfo)
static int secp256k1_jacobi32_maybe_var(const secp256k1_modinv32_signed30 *x, const secp256k1_modinv32_modinfo *modinfo)
secp256k1_modinv32_signed30 modulus
Definition: modinv32.h:21