nostril/ext/secp256k1/src/ecmult_const.h

39 lines
1.3 KiB
C

/***********************************************************************
* Copyright (c) 2015 Andrew Poelstra *
* Distributed under the MIT software license, see the accompanying *
* file COPYING or https://www.opensource.org/licenses/mit-license.php.*
***********************************************************************/
#ifndef SECP256K1_ECMULT_CONST_H
#define SECP256K1_ECMULT_CONST_H
#include "scalar.h"
#include "group.h"
/**
* Multiply: R = q*A (in constant-time for q)
*/
static void secp256k1_ecmult_const(secp256k1_gej *r, const secp256k1_ge *a, const secp256k1_scalar *q);
/**
* Same as secp256k1_ecmult_const, but takes in an x coordinate of the base point
* only, specified as fraction n/d (numerator/denominator). Only the x coordinate of the result is
* returned.
*
* If known_on_curve is 0, a verification is performed that n/d is a valid X
* coordinate, and 0 is returned if not. Otherwise, 1 is returned.
*
* d being NULL is interpreted as d=1. If non-NULL, d must not be zero. q must not be zero.
*
* Constant time in the value of q, but not any other inputs.
*/
static int secp256k1_ecmult_const_xonly(
secp256k1_fe *r,
const secp256k1_fe *n,
const secp256k1_fe *d,
const secp256k1_scalar *q,
int known_on_curve
);
#endif /* SECP256K1_ECMULT_CONST_H */