Make WebCrypto optional with config.useWebCrypto

src/crypto/public_key/rsa.js

@@ -134,12 +134,13 @@ function RSA() {
   // Generate a new random private key B bits long, using public expt E
 
   function generate(B, E, callback) {
+    var webCrypto = util.getWebCrypto();
 
     //
     // Native RSA keygen using Web Crypto
     //
 
-    if (typeof window !== 'undefined' && window.crypto && window.crypto.subtle) {
+    if (webCrypto) {
       var Euint32 = new Uint32Array([parseInt(E, 16)]); // get integer of exponent
       var Euint8 = new Uint8Array(Euint32.buffer); // get bytes of exponent
 
@@ -152,7 +153,7 @@ function RSA() {
         }
       };
 
-      var gen = window.crypto.subtle.generateKey(keyGenOpt, true, ['sign', 'verify']);
+      var gen = webCrypto.generateKey(keyGenOpt, true, ['sign', 'verify']);
       gen.then(exportKey).then(decodeKey).catch(onError);
 
       return;
@@ -161,7 +162,7 @@ function RSA() {
     function exportKey(key) {
       // export the generated keys as JsonWebKey (JWK)
       // https://tools.ietf.org/html/draft-ietf-jose-json-web-key-33
-      return window.crypto.subtle.exportKey('jwk', key.privateKey);
+      return webCrypto.exportKey('jwk', key.privateKey);
     }
 
     function decodeKey(jwk) {

src/openpgp.js

@@ -38,6 +38,7 @@ var armor = require('./encoding/armor.js'),
   message = require('./message.js'),
   cleartext = require('./cleartext.js'),
   key = require('./key.js'),
+  util = require('./util'),
   AsyncProxy = require('./worker/async_proxy.js');
 
 var asyncProxy; // instance of the asyncproxy
@@ -234,7 +235,7 @@ function generateKeyPair(options, callback) {
   }
 
   // use web worker if web crypto apis are not supported
-  if (!useWebCrypto() && useWorker(callback)) {
+  if (!util.getWebCrypto() && useWorker(callback)) {
     asyncProxy.generateKeyPair(options, callback);
     return;
   }
@@ -273,13 +274,6 @@ function useWorker(callback) {
   return true;
 }
 
-/**
- * Check for WebCrypto support
- */
-function useWebCrypto() {
-  return typeof window !== 'undefined' && window.crypto && window.crypto.subtle;
-}
-
 /**
  * Command pattern that handles async calls gracefully
  */

src/util.js

@@ -1,16 +1,16 @@
 // GPG4Browsers - An OpenPGP implementation in javascript
 // Copyright (C) 2011 Recurity Labs GmbH
-// 
+//
 // 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
@@ -193,7 +193,7 @@ module.exports = {
   },
 
   /**
-   * Convert a Uint8Array to a string. This currently functions 
+   * Convert a Uint8Array to a string. This currently functions
    * the same as bin2str.
    * @function module:util.Uint8Array2str
    * @param {Uint8Array} bin An array of (binary) integers to convert
@@ -228,7 +228,7 @@ module.exports = {
   },
 
   /**
-   * Helper function to print a debug message. Debug 
+   * Helper function to print a debug message. Debug
    * messages are only printed if
    * @link module:config/config.debug is set to true.
    * @param {String} str String of the debug message
@@ -240,7 +240,7 @@ module.exports = {
   },
 
   /**
-   * Helper function to print a debug message. Debug 
+   * Helper function to print a debug message. Debug
    * messages are only printed if
    * @link module:config/config.debug is set to true.
    * Different than print_debug because will call hexstrdump iff necessary.
@@ -265,9 +265,9 @@ module.exports = {
   /**
    * Shifting a string to n bits right
    * @param {String} value The string to shift
-   * @param {Integer} bitcount Amount of bits to shift (MUST be smaller 
+   * @param {Integer} bitcount Amount of bits to shift (MUST be smaller
    * than 9)
-   * @return {String} Resulting string. 
+   * @return {String} Resulting string.
    */
   shiftRight: function (value, bitcount) {
     var temp = util.str2bin(value);
@@ -305,5 +305,16 @@ module.exports = {
         return "SHA224";
     }
     return "unknown";
+  },
+
+  getWebCrypto: function() {
+    if (config.useWebCrypto === false) {
+      // make web crypto optional
+      return;
+    }
+
+    if (typeof window !== 'undefined' && window.crypto && window.crypto.subtle) {
+      return window.crypto.subtle;
+    }
   }
 };