tested

key.pem

@@ -0,0 +1,30 @@
+-----BEGIN RSA PRIVATE KEY-----
+Proc-Type: 4,ENCRYPTED
+DEK-Info: DES-EDE3-CBC,78E62ACC722BE51C
+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-----END RSA PRIVATE KEY-----

package.json

@@ -43,6 +43,7 @@
   },
   "dependencies": {
     "es6-promise": "3.0.2",
-    "isomorphic-fetch": "2.1.1"
+    "isomorphic-fetch": "2.1.1",
+    "ursa": "^0.9.1"
   }
 }

src/modules/node-only.js

@@ -1,5 +1,5 @@
 var FS = require('./../FamilySearch'),
-    crypto = require('crypto');
+    ursa = require('ursa');
 
 /**
  * Methods that are only supported in node.
@@ -10,35 +10,30 @@ var FS = require('./../FamilySearch'),
  * @name authentication.functions:getAccessTokenWithClientCredentials
  *
  * @description
- * Get an access token via client credentials. This is only supported in node
- * versions >= 0.12. This will throw an exception when using in the browser or
- * node versions that do not have the `crypto.privateEncrypt()` function.
+ * Get an access token via client credentials.
  * 
- * @param {String} key The `private_key` value of [crypto.privateEncrypt()](https://nodejs.org/api/crypto.html#crypto_crypto_privateencrypt_private_key_buffer)
- * @param {Integer|String} time This parameter is only available for the sake of testing.
+ * @param {String} key A PEM-encoded key. Matches the `pem` parameter of [ursa.createPrivateKey()](https://github.com/quartzjer/ursa#ursacreateprivatekeypem-password-encoding).
+ * @param {String=} password The password for descrypting the key, if necessary.
+ * @param {Integer=|String=} time This parameter is only available for the sake of testing. Do not use it in production.
  */
-FS.prototype.getAccessTokenWithClientCredentials = function(key, time){
-
-  if(!crypto.privateEncrypt){
-    throw new Error('Authentication via client credentials is not supported in the browser and requires node version 0.12 or greater.');
-  }
+FS.prototype.getAccessTokenWithClientCredentials = function(key, password, time){
 
   var self = this,
+
+      // URSA key object
+      ukey = ursa.createPrivateKey(key, password),
 
       // Get a timestamp in milliseconds
       timestamp = time || Date.now(),
 
       // Encrypt the timestamp using the private key
-      secret = crypto.privateEncrypt(key, new Buffer(timestamp + '')),
-
-      // Encode the secret into base64
-      encodedSecret = new Buffer(secret).toString('base64');
+      secret = ukey.privateEncrypt(timestamp + '', 'utf8', 'base64');
 
   // Make the request
   return self.plumbing.post(self.settings.oauthServer[self.settings.environment] + '/token', {
       'grant_type': 'client_credentials',
       'client_id': self.settings.clientId,
-      'client_secret': encodedSecret
+      'client_secret': secret
     },
     // access token endpoint says it accepts json but it doesn't
     {'Content-Type': 'application/x-www-form-urlencoded'}).then(function(response){

test/unit/authenticationSpec.js

@@ -1,4 +1,5 @@
-var url = require('url');
+var querystring = require('querystring'),
+    fs = require('fs');
 
 describe('An access token', function() {
 
@@ -29,8 +30,11 @@ describe('An access token', function() {
 
   it('is returned from getAccessTokenWithClientCredentials', function(done){
     FS.invalidateAccessToken().then(function(){
-      FS.getAccessTokenWithClientCredentials(process.env['FS_CLIENT_KEY'], 12345).then(function(accessToken){
-        expect(url.parse(__getHttpRequests()[0].url, true)['client_secret']).toBe('foo');
+      FS.getAccessTokenWithClientCredentials(fs.readFileSync('key.pem'), process.env['FS_KEY_PASSWORD'], 1447773012436).then(function(accessToken){
+        var request = __getHttpRequests()[3],
+            body = request.body,
+            params = querystring.parse(body);
+        expect(params['client_secret']).toBe('vAo5bmjV2SZj9XCZJ5HAew6bFwrz1uuPyyQMfjlAddoELBKkZdTsaua7iK6J0AZPu9vo8Nzd/Nc/r1UHiSVR0N4N5q8DX8p5jDe+/LRzwyog1tS6zW/ke8S/x+eSNtbMhXAsHixMJkwrncMgmhoqEYX99Glh4wc4CNVU+eSB8seBDG37KTlUsEK//gm+vbt2/v6A3U4CEp7BTPMIGNWoWm0548zzO01cnZ2zezXMuwDARH0ENy3gQ37sG2tI+9MBHijO7Q8TG+4GfbVzz/QOQuDDL/rf9MonZcFF+pdaESDk7NpRGeXKGfCpHHHHQF7Eyobisdrl35WGowdCwnUzew==');
         expect(accessToken).toBe('2YoTnFdFEjr1zCsicMWpAA');
         done();
       });

test/unit/helpers.js

@@ -70,6 +70,16 @@ function loadFile(filename){
  * @param opts
  */
 function httpMock(req, res) {
+
+  // Make the request body available to tests
+  var body = '';
+  req.on('data', function(data){
+    body += data;
+  });
+  req.on('end', function(){
+    req.body = body;
+  });
+
   requests.push(req);
 
   var filename = getFilename(req);