@toruslabs/ffjavascript/dist/lib.cjs/futils.js

Finite Field Library in Javascript

'use strict';

var scalar = require('./scalar.js');

/*
    Copyright 2018 0kims association.

    This file is part of snarkjs.

    snarkjs is a free software: you can redistribute it and/or
    modify it under the terms of the GNU General Public License as published by the
    Free Software Foundation, either version 3 of the License, or (at your option)
    any later version.

    snarkjs is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
    or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
    more details.

    You should have received a copy of the GNU General Public License along with
    snarkjs. If not, see <https://www.gnu.org/licenses/>.
*/
function exp(F, base, e) {
  if (scalar.isZero(e)) return F.one;
  const n = scalar.bits(e);
  if (n.length == 0) return F.one;
  let res = base;
  for (let i = n.length - 2; i >= 0; i--) {
    res = F.square(res);
    if (n[i]) {
      res = F.mul(res, base);
    }
  }
  return res;
}

exports.exp = exp;