pqp/dist/es/crypto/qcmdpc.js

NodeJS version of libPQP

'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});

var _createClass = function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; }();

var _public_key = require('./public_key');

var _public_key2 = _interopRequireDefault(_public_key);

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

var _randomgen2 = _interopRequireDefault(_randomgen);

var _arithmetic = require('../operations/arithmetic');

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

var McEliece = function () {
  function McEliece() {
    _classCallCheck(this, McEliece);

    this.randgen = new _randomgen2.default();
  }

  _createClass(McEliece, [{
    key: 'set_private_key',
    value: function set_private_key(priv_key) {
      this.H_0 = priv_key.H_0;
      this.H_1 = priv_key.H_1;
      this.G = (0, _arithmetic.mul_poly)(priv_key.H_0, priv_key.H_1inv); // compute public key

      this.block_length = priv_key.block_length;
      this.block_error = priv_key.block_error;
      this.block_weight = priv_key.block_weight;
    }
  }, {
    key: 'get_public_key',
    value: function get_public_key() {
      var pub_key = new _public_key2.default();
      pub_key.G = this.G;
      pub_key.block_error = this.block_error;
      return pub_key;
    }
  }, {
    key: 'encrypt',
    value: function encrypt(pub_key, m) {
      // non-constant weight to achieve cipertext indistinguishability
      var temp = (0, _arithmetic.mul_poly)(pub_key.G, m.clone());
      var t = this.randgen.get_random_weight_vector(pub_key.block_length, pub_key.block_error + this.randgen.flip_coin());
      var v = temp.add(t).mod(2);
      t = this.randgen.get_random_weight_vector(pub_key.block_length, pub_key.block_error + this.randgen.flip_coin());
      var u = m.add(t).mod(2);
      return [u, v];
    }
  }, {
    key: 'syndrome',
    value: function syndrome(c_0, c_1) {
      return (0, _arithmetic.mul_poly)(this.H_0, c_0).add((0, _arithmetic.mul_poly)(this.H_1, c_1)).mod(2);
    }
  }, {
    key: 'decrypt',
    value: function decrypt(c_0, c_1) {
      var synd = this.syndrome(c_0, c_1);
      // compute correlations with syndrome
      var H0_ind = this.H_0.nonzero();
      var H1_ind = this.H_1.nonzero();

      var kBL = this.block_length;
      var unsat_H0 = Float32Array.createZero(kBL);
      H0_ind.forEach(function (i) {
        for (var j = 0; j < synd.length; ++j) {
          if (synd[j]) {
            var idx = (j + kBL - i) % kBL;
            unsat_H0[idx] += 1;
          }
        }
      });

      var unsat_H1 = Float32Array.createZero(kBL);
      H1_ind.forEach(function (i) {
        for (var j = 0; j < synd.length; ++j) {
          if (synd[j]) {
            var idx = (j + kBL - i) % kBL;
            unsat_H1[idx] += 1;
          }
        }
      });

      var rounds = 10;
      var delta = 5;
      var threshold = 100;
      var r = 0;

      while (true) {
        var max_unsat = Math.max(unsat_H0.max(), unsat_H1.max());

        // if so, we are done decoding
        if (max_unsat == 0) {
          break;
        }

        // we have reach the upper bound on rounds
        if (r >= rounds) {
          throw new Error('Decryption error');
          break;
        }
        r += 1;

        // update threshold
        if (max_unsat > delta) {
          threshold = max_unsat - delta;
        }
        var round_unsat_H0 = unsat_H0.clone();
        var round_unsat_H1 = unsat_H1.clone();

        // first block sweep

        var _loop = function _loop(i) {
          if (round_unsat_H0[i] <= threshold) {
            return 'continue';
          }

          H0_ind.forEach(function (j) {
            var increase = synd[(i + j) % kBL] == 0;

            H0_ind.forEach(function (k) {
              var m = (i + j - k + kBL) % kBL;
              if (increase) unsat_H0[m] += 1;else unsat_H0[m] += -1;
            });

            H1_ind.forEach(function (k) {
              var m = (i + j - k + kBL) % kBL;
              if (increase) unsat_H1[m] += 1;else unsat_H1[m] += -1;
            });

            synd[(i + j) % kBL] ^= 1;
          });

          c_0[i] ^= 1;
        };

        for (var i = 0; i < kBL; ++i) {
          var _ret = _loop(i);

          if (_ret === 'continue') continue;
        }

        // second block sweep

        var _loop2 = function _loop2(i) {
          if (round_unsat_H1[i] <= threshold) {
            return 'continue';
          }

          H1_ind.forEach(function (j) {
            var increase = synd[(i + j) % kBL] == 0;

            H0_ind.forEach(function (k) {
              var m = (i + j - k + kBL) % kBL;
              if (increase) unsat_H0[m] += 1;else unsat_H0[m] += -1;
            });

            H1_ind.forEach(function (k) {
              var m = (i + j - k + kBL) % kBL;
              if (increase) unsat_H1[m] += 1;else unsat_H1[m] += -1;
            });
            synd[(i + j) % kBL] ^= 1;
          });

          c_1[i] ^= 1;
        };

        for (var i = 0; i < kBL; ++i) {
          var _ret2 = _loop2(i);

          if (_ret2 === 'continue') continue;
        }
      }
      return c_0;
    }
  }]);

  return McEliece;
}();

exports.default = McEliece;