Add Web Key Directory lookup

This change implements Web Key Directory lookup using user's e-mail
address. The target host is the same as the e-mail's domain and the
local-part is hashed with SHA-1 and encoded using Z-Base32 encoding.

Implemented is basic flow of version 06 of OpenPGP Web Key Directory
draft [0].

It was necessary to update node-fetch package to allow returning array
buffers from HTTP responses.

If openpgpjs is used in the browser all keys retrieved from Web Key
Directory should have `Access-Control-Allow-Origin` header set to `*`
(including 404 Not found responses).

[0]: https://datatracker.ietf.org/doc/draft-koch-openpgp-webkey-service/

npm-shrinkwrap.json

@@ -2325,14 +2325,6 @@
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       "dev": true
     },
-    "encoding": {
-      "version": "0.1.12",
-      "resolved": "https://registry.npmjs.org/encoding/-/encoding-0.1.12.tgz",
-      "integrity": "sha1-U4tm8+5izRq1HsMjgp0flIDHS+s=",
-      "requires": {
-        "iconv-lite": "0.4.19"
-      }
-    },
     "error-ex": {
       "version": "1.3.1",
       "resolved": "https://registry.npmjs.org/error-ex/-/error-ex-1.3.1.tgz",
@@ -5221,11 +5213,6 @@
       "integrity": "sha512-qgDYXFSR5WvEfuS5dMj6oTMEbrrSaM0CrFk2Yiq/gXnBvD9pMa2jGXxyhGLfvhZpuMZe18CJpFxAt3CRs42NMg==",
       "dev": true
     },
-    "is-stream": {
-      "version": "1.1.0",
-      "resolved": "https://registry.npmjs.org/is-stream/-/is-stream-1.1.0.tgz",
-      "integrity": "sha1-EtSj3U5o4Lec6428hBc66A2RykQ="
-    },
     "is-typedarray": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/is-typedarray/-/is-typedarray-1.0.0.tgz",
@@ -6006,13 +5993,9 @@
       }
     },
     "node-fetch": {
-      "version": "1.7.3",
-      "resolved": "https://registry.npmjs.org/node-fetch/-/node-fetch-1.7.3.tgz",
-      "integrity": "sha512-NhZ4CsKx7cYm2vSrBAr2PvFOe6sWDf0UYLRqA6svUYg7+/TSfVAu49jYC4BvQ4Sms9SZgdqGBgroqfDhJdTyKQ==",
-      "requires": {
-        "encoding": "0.1.12",
-        "is-stream": "1.1.0"
-      }
+      "version": "2.1.2",
+      "resolved": "https://registry.npmjs.org/node-fetch/-/node-fetch-2.1.2.tgz",
+      "integrity": "sha1-q4hOjn5X44qUR1POxwb3iNF2i7U="
     },
     "node-localstorage": {
       "version": "1.3.0",

package.json

@@ -80,7 +80,7 @@
     "compressjs": "github:openpgpjs/compressjs",
     "elliptic": "github:openpgpjs/elliptic",
     "hash.js": "^1.1.3",
-    "node-fetch": "^1.7.3",
+    "node-fetch": "^2.1.2",
     "node-localstorage": "~1.3.0",
     "pako": "^1.0.6",
     "rusha": "^0.8.12"

src/index.js

@@ -141,3 +141,9 @@ export { default as AsyncProxy } from './worker/async_proxy';
  * @name module:openpgp.HKP
  */
 export { default as HKP } from './hkp';
+
+/**
+ * @see module:wkd
+ * @name module:openpgp.WKD
+ */
+export { default as WKD } from './wkd';

src/wkd.js

@@ -0,0 +1,77 @@
+// OpenPGP.js - An OpenPGP implementation in javascript
+// Copyright (C) 2018 Wiktor Kwapisiewicz
+//
+// This library is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public
+// License as published by the Free Software Foundation; either
+// version 3.0 of the License, or (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+
+/**
+ * @fileoverview This class implements a client for the Web Key Directory (wkd) protocol
+ * in order to lookup keys on designated servers.
+ * See: https://datatracker.ietf.org/doc/draft-koch-openpgp-webkey-service/
+ * @module wkd
+ */
+
+import util from './util';
+import crypto from './crypto';
+import * as keyMod from './key';
+
+/**
+ * Initialize the WKD client
+ * @constructor
+ */
+function WKD() {
+  this._fetch = typeof window !== 'undefined' ? window.fetch : require('node-fetch');
+}
+
+/**
+ * Search for a public key using Web Key Directory protocol.
+ * @param   {String}   options.email         User's email.
+ * @param   {Boolean}  options.rawBytes      Returns Uint8Array instead of parsed key.
+ * @returns {Promise<Uint8Array|
+ *           {keys: Array<module:key.Key>,
+ *            err: (Array<Error>|null)}>}     The public key.
+ * @async
+ */
+WKD.prototype.lookup = function(options) {
+  const fetch = this._fetch;
+
+  if (!options.email) {
+    throw new Error('You must provide an email parameter!');
+  }
+
+  if (!util.isEmailAddress(options.email)) {
+      throw new Error('Invalid e-mail address.');
+  }
+
+  const [, localPart, domain] = /(.*)@(.*)/.exec(options.email);
+  const localEncoded = util.encodeZBase32(crypto.hash.sha1(util.str_to_Uint8Array(localPart.toLowerCase())));
+
+  const url = `https://${domain}/.well-known/openpgpkey/hu/${localEncoded}`;
+
+  return fetch(url).then(function(response) {
+    if (response.status === 200) {
+      return response.arrayBuffer();
+    }
+  }).then(function(publicKey) {
+    if (publicKey) {
+        const rawBytes = new Uint8Array(publicKey);
+        if (options.rawBytes) {
+          return rawBytes;
+        }
+        return keyMod.read(rawBytes);
+    }
+  });
+};
+
+export default WKD;

test/general/index.js

@@ -7,6 +7,7 @@ describe('General', function () {
   require('./key.js');
   require('./openpgp.js');
   require('./hkp.js');
+  require('./wkd.js');
   require('./oid.js');
   require('./ecc_nist.js');
   require('./x25519.js');

test/general/wkd.js

@@ -0,0 +1,48 @@
+const openpgp = typeof window !== 'undefined' && window.openpgp ? window.openpgp : require('../../dist/openpgp');
+
+const chai = require('chai');
+
+const { expect } = chai;
+
+describe('WKD unit tests', function() {
+  this.timeout(60000);
+
+  let wkd;
+
+  beforeEach(function() {
+    wkd = new openpgp.WKD();
+  });
+
+  afterEach(function() {});
+
+  describe('lookup', function() {
+    it('by email address should work', function() {
+      return wkd.lookup({
+        email: 'test-wkd@metacode.biz',
+        rawBytes: true
+      }).then(function(key) {
+        expect(key).to.exist;
+        expect(key).to.be.an.instanceof(Uint8Array);
+      });
+    });
+
+    it('by email address should work', function() {
+      return wkd.lookup({
+        email: 'test-wkd@metacode.biz'
+      }).then(function(key) {
+        expect(key).to.exist;
+        expect(key).to.have.property('keys');
+        expect(key.keys).to.have.lengthOf(1);
+      });
+    });
+
+    it('by email address should not find a key', function() {
+      return wkd.lookup({
+        email: 'test-wkd-does-not-exist@metacode.biz'
+      }).then(function(key) {
+        expect(key).to.be.undefined;
+      });
+    });
+  });
+
+});