crypto-conditions/dist/node/crypto/rsa.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 _concat = _interopRequireDefault(require("@babel/runtime-corejs3/core-js-stable/instance/concat"));

var _slice = _interopRequireDefault(require("@babel/runtime-corejs3/core-js-stable/instance/slice"));

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

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

var _crypto = require("crypto");

var _pss = _interopRequireDefault(require("../crypto/pss"));

var _pem = _interopRequireDefault(require("../util/pem"));

/**
 * @module types
 */

/**
 * RSA-PSS using Node crypto module.
 *
 * This class combines Node's native crypto functionality with PSS padding
 * implemented in this library.
 */
var Rsa = /*#__PURE__*/function () {
  function Rsa(opts) {
    (0, _classCallCheck2.default)(this, Rsa);
    opts = opts || {};
    this.hashAlgorithm = opts.hashAlgorithm || 'sha256';
    this.pss = new _pss.default({
      hashAlgorithm: this.hashAlgorithm
    });
  }
  /**
   * Get the length in bits of an RSA modulus.
   *
   * @param {Buffer} modulus RSA modulus.
   * @return {Number} Number of bits in RSA modulus.
   */


  (0, _createClass2.default)(Rsa, [{
    key: "getModulusBitLength",
    value: function getModulusBitLength(modulus) {
      var modulusHighByteBitLength = modulus[0].toString(2).length;
      var modulusBitLength = (modulus.length - 1) * 8 + modulusHighByteBitLength;
      return modulusBitLength;
    }
    /**
     * Sign a message using RSA-PSS.
     *
     * @param {String} privateKey PEM-encoded RSA private key.
     * @param {Buffer} message Message to sign.
     * @return {Buffer} RSA signature.
     */

  }, {
    key: "sign",
    value: function sign(privateKey, message) {
      // Calculate modulus bit length
      var modulus = _pem.default.modulusFromPrivateKey(privateKey);

      var modulusBitLength = this.getModulusBitLength(modulus); // Pad message using PSS

      var encodedMessage = this.pss.encode(message, modulusBitLength - 1); // OpenSSL expects the message buffer to be the same length (in bytes) as
      // the modulus.

      var paddedMessage = encodedMessage.length < modulus.length ? (0, _concat.default)(Buffer).call(Buffer, [Rsa.ZERO_BYTE, encodedMessage]) : encodedMessage; // Sign

      return (0, _crypto.privateEncrypt)({
        key: privateKey,
        padding: _crypto.constants.RSA_NO_PADDING
      }, paddedMessage);
    }
    /**
     * Verify a RSA-PSS signature.
     *
     * @param {Buffer} modulus RSA public modulus.
     * @param {Buffer} message Message the signature should correspond to.
     * @param {Buffer} signature RSA signature.
     * @return {Boolean} Whether the signature is valid or not.
     */

  }, {
    key: "verify",
    value: function verify(modulus, message, signature) {
      // Verify signature
      var publicKey = _pem.default.modulusToPem(modulus);

      var paddedMessage = (0, _crypto.publicDecrypt)({
        key: publicKey,
        padding: _crypto.constants.RSA_NO_PADDING
      }, signature); // OpenSSL returns a buffer that fits the bitlength of the modulus, but we
      // need this buffer to be just long enough to fit the bitlength of the
      // encodedMessage, which is one bit shorter.

      var modulusBitLength = this.getModulusBitLength(modulus);
      var encodedMessage = modulusBitLength % 8 === 1 ? (0, _slice.default)(paddedMessage).call(paddedMessage, 1) : paddedMessage; // Verify message padding

      return this.pss.verify(message, encodedMessage, modulusBitLength - 1);
    }
  }]);
  return Rsa;
}(); // Used to add a zero for padding


Rsa.ZERO_BYTE = Buffer.from([0]);
var _default = Rsa;
exports.default = _default;