crypto-conditions/dist/node/crypto/mgf1.js

Implementation of crypto-conditions in JavaScript

"use strict";

var _Object$defineProperty = require("@babel/runtime-corejs3/core-js-stable/object/define-property");

var _interopRequireDefault = require("@babel/runtime-corejs3/helpers/interopRequireDefault");

_Object$defineProperty(exports, "__esModule", {
  value: true
});

exports.default = void 0;

var _classCallCheck2 = _interopRequireDefault(require("@babel/runtime-corejs3/helpers/classCallCheck"));

var _createClass2 = _interopRequireDefault(require("@babel/runtime-corejs3/helpers/createClass"));

var _crypto = require("crypto");

var Mgf1 = /*#__PURE__*/function () {
  function Mgf1(opts) {
    (0, _classCallCheck2.default)(this, Mgf1);
    opts = opts || {};
    this.hashAlgorithm = opts.hashAlgorithm || 'sha256';
    this.hashLength = (0, _crypto.createHash)(this.hashAlgorithm).digest().length;
    this.saltLength = this.hashLength;
  }
  /**
   * Generate MGF1 full domain hash.
   *
   * Implementation of RFC 3447, section B.2.1.
   *
   * @param {Buffer} seed Seed from which mask is generated.
   * @param {Number} maskLength Intended length of the mask in bytes.
   * @return {Buffer} Mask
   */


  (0, _createClass2.default)(Mgf1, [{
    key: "generate",
    value: function generate(seed, maskLength) {
      var result = Buffer.alloc(maskLength);
      var len = Math.ceil(maskLength / this.hashLength);

      for (var i = 0; i < len; i++) {
        var counter = Buffer.alloc(4);
        counter.writeInt32BE(i, 0);
        var hash = (0, _crypto.createHash)(this.hashAlgorithm).update(seed).update(counter).digest();
        hash.copy(result, i * this.hashLength);
      }

      return result;
    }
  }]);
  return Mgf1;
}();

var _default = Mgf1;
exports.default = _default;