generateSignatureJwk works with both ursa and forge :)

node.js

@@ -110,7 +110,15 @@ function create(deps) {
   };
   RSA._forgeGenerateSig = function (keypair, sha256Buf) {
     var forge = require('node-forge');
-    var md = forge.util.createBuffer(sha256Buf.toString('binary'), 'binary');
+    var bufF = forge.util.createBuffer(sha256Buf.toString('binary'), 'binary');
+    var md = {
+      algorithm: 'sha256'
+    , blockLength: 64
+    , digestLength: 20
+    , digest: function () {
+        return bufF;
+      }
+    };
     var sigF = keypair._forge.sign(md);
     var sig64 = RSA.utils.toWebsafeBase64(
       new Buffer(forge.util.bytesToHex(sigF), "hex").toString('base64')

tests/generate-sig.js

@@ -16,7 +16,8 @@ var keypair = {
   }
 };
 
-var result = {
+/*
+var ursaResult = {
   "header": {
     "alg": "RS256",
     "jwk": {
@@ -29,6 +30,20 @@ var result = {
   "payload": "JLzF1NBNCV3kfbJ5sFaFyX94fJuL2H-IzaoBN-ciiHk",
   "signature": "Wb2al5SDyh5gjmkV79MK9m3sfNBBPjntSKor-34BBoGwr6n8qEnBmqB1Y4zbo-5rmvsoPmJsnRlP_hRiUY86zSAQyfbisTGrGBl0IQ7ditpkfYVm0rBWJ8WnYNqYNp8K3qcD7NW72tsy-XoWEjNlz4lWJeRdEG2Nt4CJgnREH4Y"
 };
+var forgeResult = {
+  "header": {
+    "alg": "RS256",
+    "jwk": {
+      "kty": "RSA",
+      "n": "AMJubTfOtAarnJytLE8fhNsEI8wnpjRvBXGK/Kp0675J10ORzxyMLqzIZF3tcrUkKBrtdc79u4X0GocDUgukpfkY+2UPUS/GxehUYbYrJYWOLkoJWzxn7wfoo9X1JgvBMY6wHQnTKvnzZdkom2FMhGxkLaEUGDSfsNznTTZNBBg9",
+      "e": "AQAB"
+    }
+  },
+  "protected": "eyJub25jZSI6IjhlZjU2MjRmNWVjOWQzZWYifQ",
+  "payload": "JLzF1NBNCV3kfbJ5sFaFyX94fJuL2H-IzaoBN-ciiHk",
+  "signature": "Wb2al5SDyh5gjmkV79MK9m3sfNBBPjntSKor-34BBoGwr6n8qEnBmqB1Y4zbo-5rmvsoPmJsnRlP_hRiUY86zSAQyfbisTGrGBl0IQ7ditpkfYVm0rBWJ8WnYNqYNp8K3qcD7NW72tsy-XoWEjNlz4lWJeRdEG2Nt4CJgnREH4Y"
+};
+*/
 
 var jws = RSA.generateSignatureJwk(
   keypair