pqp/dist/es/operations/arithmetic.js

NodeJS version of libPQP

'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.mul_poly = mul_poly;
exports.square_sparse_poly = square_sparse_poly;
exports.exp_poly = exp_poly;

require('../utils/polyfill');

var _randomgen = require('./randomgen');

function mul_poly(x, y) {
  var length = x.length;
  x = x.fft();
  y = y.fft();
  var temp = x.complexMultiply(y).ifft(length).round().mod(2);
  return temp;
}

function square_sparse_poly(x) {
  var times = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : 1;

  var indices = Float32Array.from(x.nonzero());
  var mod = x.length;
  var result = (0, _randomgen.zeroArray)(mod);
  indices = indices.multiply(Math.pow(2, times) % mod);
  indices.forEach(function (index) {
    var idx = index % mod;
    result[idx] = result[idx] ^ 1;
  });
  return result;
}

function exp_poly(x, n) {
  var length = x.length;
  var y = (0, _randomgen.zeroArray)(length);
  y[0] = 1;

  while (n.gt(1)) {
    if (n.mod(2) == 0) {
      x = square_sparse_poly(x);
      n = n.div(2);
    } else {
      // precision does not allow us to stay in FFT domain
      // hence, interchanging ifft(fft).
      var X = x.clone().fft();
      var Y = y.clone().fft();

      var temp = X.complexMultiply(Y).ifft(length);
      y = temp.round().mod(2);
      x = square_sparse_poly(x);
      n = n.sub(1);
      n = n.div(2);
    }
  }

  return mul_poly(x, y).round().mod(2);
}