github.com/ethereum/go-ethereum@v1.16.1/crypto/secp256k1/libsecp256k1/src/ecmult_const.h (about)

     1  /***********************************************************************
     2   * Copyright (c) 2015 Andrew Poelstra                                  *
     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_ECMULT_CONST_H
     8  #define SECP256K1_ECMULT_CONST_H
     9  
    10  #include "scalar.h"
    11  #include "group.h"
    12  
    13  /**
    14   * Multiply: R = q*A (in constant-time for q)
    15   */
    16  static void secp256k1_ecmult_const(secp256k1_gej *r, const secp256k1_ge *a, const secp256k1_scalar *q);
    17  
    18  /**
    19   * Same as secp256k1_ecmult_const, but takes in an x coordinate of the base point
    20   * only, specified as fraction n/d (numerator/denominator). Only the x coordinate of the result is
    21   * returned.
    22   *
    23   * If known_on_curve is 0, a verification is performed that n/d is a valid X
    24   * coordinate, and 0 is returned if not. Otherwise, 1 is returned.
    25   *
    26   * d being NULL is interpreted as d=1. If non-NULL, d must not be zero. q must not be zero.
    27   *
    28   * Constant time in the value of q, but not any other inputs.
    29   */
    30  static int secp256k1_ecmult_const_xonly(
    31      secp256k1_fe *r,
    32      const secp256k1_fe *n,
    33      const secp256k1_fe *d,
    34      const secp256k1_scalar *q,
    35      int known_on_curve
    36  );
    37  
    38  #endif /* SECP256K1_ECMULT_CONST_H */