--- a/services/sync/Weave.js
+++ b/services/sync/Weave.js
@@ -108,17 +108,16 @@ WeaveService.prototype = {
           // this check into this file if our above code is yielding too
           // many false positives.
           Components.utils.import("resource://services-sync/main.js");
           isConfigured = Weave.Status.checkSetup() != Weave.CLIENT_NOT_CONFIGURED;
         }
         let getHistogramById = Services.telemetry.getHistogramById;
         getHistogramById("WEAVE_CONFIGURED").add(isConfigured);
         if (isConfigured) {
-          getHistogramById("WEAVE_CONFIGURED_MASTER_PASSWORD").add(Utils.mpEnabled());
           this.ensureLoaded();
         }
       }
     }, 10000, Ci.nsITimer.TYPE_ONE_SHOT);
   },
 
   /**
    * Whether Sync appears to be enabled.

--- a/services/sync/modules/util.js
+++ b/services/sync/modules/util.js
@@ -18,16 +18,20 @@ XPCOMUtils.defineLazyModuleGetter(this, 
 
 // FxAccountsCommon.js doesn't use a "namespace", so create one here.
 XPCOMUtils.defineLazyGetter(this, "FxAccountsCommon", function() {
   let FxAccountsCommon = {};
   Cu.import("resource://gre/modules/FxAccountsCommon.js", FxAccountsCommon);
   return FxAccountsCommon;
 });
 
+XPCOMUtils.defineLazyServiceGetter(this, "cryptoSDR",
+                                   "@mozilla.org/login-manager/crypto/SDR;1",
+                                   "nsILoginManagerCrypto");
+
 /*
  * Custom exception types.
  */
 class LockException extends Error {
   constructor(message) {
     super(message);
     this.name = "LockException";
   }
@@ -474,45 +478,30 @@ this.Utils = {
     return foo.concat(Utils.arraySub(bar, foo));
   },
 
   bind2: function Async_bind2(object, method) {
     return function innerBind() { return method.apply(object, arguments); };
   },
 
   /**
-   * Is there a master password configured, regardless of current lock state?
-   */
-  mpEnabled: function mpEnabled() {
-    let tokenDB = Cc["@mozilla.org/security/pk11tokendb;1"]
-                    .getService(Ci.nsIPK11TokenDB);
-    let token = tokenDB.getInternalKeyToken();
-    return token.hasPassword;
-  },
-
-  /**
    * Is there a master password configured and currently locked?
    */
-  mpLocked: function mpLocked() {
-    let tokenDB = Cc["@mozilla.org/security/pk11tokendb;1"]
-                    .getService(Ci.nsIPK11TokenDB);
-    let token = tokenDB.getInternalKeyToken();
-    return token.hasPassword && !token.isLoggedIn();
+  mpLocked() {
+    return !cryptoSDR.isLoggedIn;
   },
 
   // If Master Password is enabled and locked, present a dialog to unlock it.
   // Return whether the system is unlocked.
-  ensureMPUnlocked: function ensureMPUnlocked() {
-    if (!Utils.mpLocked()) {
-      return true;
+  ensureMPUnlocked() {
+    if (cryptoSDR.uiBusy) {
+      return false;
     }
-    let sdr = Cc["@mozilla.org/security/sdr;1"]
-                .getService(Ci.nsISecretDecoderRing);
     try {
-      sdr.encryptString("bacon");
+      cryptoSDR.encrypt("bacon");
       return true;
     } catch (e) {}
     return false;
   },
 
   /**
    * Return a value for a backoff interval.  Maximum is eight hours, unless
    * Status.backoffInterval is higher.