diff --git a/src/applications/auth/factor/PhabricatorAuthFactor.php b/src/applications/auth/factor/PhabricatorAuthFactor.php
--- a/src/applications/auth/factor/PhabricatorAuthFactor.php
+++ b/src/applications/auth/factor/PhabricatorAuthFactor.php
@@ -413,8 +413,8 @@
     $sync_type = PhabricatorAuthMFASyncTemporaryTokenType::TOKENTYPE;
     $sync_token = null;
 
-    $sync_key = $request->getStr($this->getMFASyncTokenFormKey());
-    if (strlen($sync_key)) {
+    $sync_key = $request->getStr($this->getMFASyncTokenFormKey(), '');
+    if ($sync_key !== '') {
       $sync_key_digest = PhabricatorHash::digestWithNamedKey(
         $sync_key,
         PhabricatorAuthMFASyncTemporaryTokenType::DIGEST_KEY);
diff --git a/src/applications/settings/panel/PhabricatorMultiFactorSettingsPanel.php b/src/applications/settings/panel/PhabricatorMultiFactorSettingsPanel.php
--- a/src/applications/settings/panel/PhabricatorMultiFactorSettingsPanel.php
+++ b/src/applications/settings/panel/PhabricatorMultiFactorSettingsPanel.php
@@ -257,7 +257,7 @@
     // example, with SMS).
     if (!$request->isFormPost() || !$request->getBool('mfa.start')) {
       $enroll = $selected_provider->getEnrollMessage();
-      if (!strlen($enroll)) {
+      if (!phutil_nonempty_string($enroll)) {
         $enroll = $selected_provider->getEnrollDescription($viewer);
       }