js-ecutils/dist/npm/protocols/diffie_hellman.js

JavaScript Library for Elliptic Curve Cryptography: key exchanges (Diffie-Hellman, Massey-Omura), ECDSA signatures, and Koblitz encoding. Suitable for crypto education and secure systems.

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.DiffieHellman = void 0;
var _registry = require("../curves/registry.js");
function _typeof(o) { "@babel/helpers - typeof"; return _typeof = "function" == typeof Symbol && "symbol" == typeof Symbol.iterator ? function (o) { return typeof o; } : function (o) { return o && "function" == typeof Symbol && o.constructor === Symbol && o !== Symbol.prototype ? "symbol" : typeof o; }, _typeof(o); }
function _classCallCheck(a, n) { if (!(a instanceof n)) throw new TypeError("Cannot call a class as a function"); }
function _defineProperties(e, r) { for (var t = 0; t < r.length; t++) { var o = r[t]; o.enumerable = o.enumerable || !1, o.configurable = !0, "value" in o && (o.writable = !0), Object.defineProperty(e, _toPropertyKey(o.key), o); } }
function _createClass(e, r, t) { return r && _defineProperties(e.prototype, r), t && _defineProperties(e, t), Object.defineProperty(e, "prototype", { writable: !1 }), e; }
function _toPropertyKey(t) { var i = _toPrimitive(t, "string"); return "symbol" == _typeof(i) ? i : i + ""; }
function _toPrimitive(t, r) { if ("object" != _typeof(t) || !t) return t; var e = t[Symbol.toPrimitive]; if (void 0 !== e) { var i = e.call(t, r || "default"); if ("object" != _typeof(i)) return i; throw new TypeError("@@toPrimitive must return a primitive value."); } return ("string" === r ? String : Number)(t); } /**
 * Elliptic Curve Diffie-Hellman (ECDH) key exchange protocol.
 *
 * Protocol:
 *     1. Alice computes her public key:  H_A = d_A · G
 *     2. Bob computes his public key:    H_B = d_B · G
 *     3. Shared secret:  S = d_A · H_B = d_B · H_A = d_A · d_B · G
 *
 * Security relies on the Elliptic Curve Discrete Logarithm Problem
 * (ECDLP): given G and Q = d·G, it is computationally infeasible to
 * recover the private scalar d.
 *
 * Usage:
 *
 *     const alice = new DiffieHellman(0xAn, 'secp256k1')
 *     const bob   = new DiffieHellman(0xBn, 'secp256k1')
 *
 *     const sharedAlice = alice.computeSharedSecret(bob.publicKey)
 *     const sharedBob   = bob.computeSharedSecret(alice.publicKey)
 *     // sharedAlice.x === sharedBob.x
 */
/**
 * Elliptic Curve Diffie-Hellman key exchange.
 */
var DiffieHellman = exports.DiffieHellman = /*#__PURE__*/function () {
  /**
   * @param {BigInt} privateKey          - The private scalar d.
   * @param {string} [curveName='secp256k1'] - Name of the curve.
   */
  function DiffieHellman(privateKey) {
    var curveName = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : 'secp256k1';
    _classCallCheck(this, DiffieHellman);
    this.privateKey = privateKey;
    this.curveName = curveName;
    Object.freeze(this);
  }
  return _createClass(DiffieHellman, [{
    key: "_G",
    get: function get() {
      return (0, _registry.getGenerator)(this.curveName);
    }

    /**
     * Compute the public key: H = d · G.
     */
  }, {
    key: "publicKey",
    get: function get() {
      return this._G.mul(this.privateKey);
    }

    /**
     * Compute the shared secret from another party's public key.
     *
     *     S = d · Q_other = d · d_other · G
     *
     * @param {Point} otherPublicKey - The other party's public key point Q.
     * @returns {Point} The shared secret point.
     */
  }, {
    key: "computeSharedSecret",
    value: function computeSharedSecret(otherPublicKey) {
      return otherPublicKey.mul(this.privateKey);
    }
  }]);
}();
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