diff --git a/www/common/cryptpad-common.js b/www/common/cryptpad-common.js
index d03371914..6a5a66047 100644
--- a/www/common/cryptpad-common.js
+++ b/www/common/cryptpad-common.js
@@ -416,7 +416,7 @@ define([
         });
     };
 
-    common.writeLoginBlock = function (data, cb) { // XXX restricted-registration
+    common.writeLoginBlock = function (data, cb) {
         postMessage('WRITE_LOGIN_BLOCK', data, function (obj) {
             cb(obj);
         });
@@ -1746,7 +1746,7 @@ define([
             });
         });
     };
-    common.changeUserPassword = function (Crypt, edPublic, data, cb) { // XXX restricted-registration
+    common.changeUserPassword = function (Crypt, edPublic, data, cb) {
         if (!edPublic) {
             return void cb({
                 error: 'E_NOT_LOGGED_IN'
@@ -1855,6 +1855,9 @@ define([
             };
 
             var content = Block.serialize(JSON.stringify(temp), blockKeys);
+            console.error("OLD AND NEW BLOCK KEYS", oldBlockKeys, blockKeys);
+            // XXX ignored unless restricted registration is active?
+            // content.registrationProof = Block.proveAncestor();
 
             console.log("writing new login block");
             common.writeLoginBlock(content, waitFor(function (obj) {
diff --git a/www/common/outer/login-block.js b/www/common/outer/login-block.js
index ef3a38676..46f5158af 100644
--- a/www/common/outer/login-block.js
+++ b/www/common/outer/login-block.js
@@ -86,6 +86,30 @@ define([
         };
     };
 
+    Block.proveAncestor = function (O /* oldBlockKeys */, N /* newBlockKeys */) {
+        N = N;
+/*
+        var registrationProof;
+        var registrationSig;
+        if (keys.previous) {
+            // XXX restricted-registration
+            // sign the publicKey of the new key with the old key
+
+            // your existing block's publicKey
+            // the new block's publicKey
+            // some proof of recency to prevent replays?
+            // a signature of the whole thing
+
+            // registrationProof = [oldPublicKey, newPublicKey];
+            // registrationSig = sign(registrationProof, oldPrivateKey);
+        }
+*/
+
+// needed for password change with restricted registration
+//registrationProof: registrationProof? Nacl.util.encodeBase64(registrationProof): undefined,
+//registrationSig: registrationSig? Nacl.util.encode
+    };
+
     Block.remove = function (keys) {
         // sign the hash of the text 'DELETE_BLOCK'
         var sig = Nacl.sign.detached(Nacl.hash(