diff --git a/src/security/sec-rule-specific.cpp b/src/security/sec-rule-specific.cpp
index 75f45b9..af89e91 100644
--- a/src/security/sec-rule-specific.cpp
+++ b/src/security/sec-rule-specific.cpp
@@ -66,8 +66,14 @@
 
   try
     {
-      SignatureWithPublicKey sig(data.getSignature());
-      Name signerName = sig.getKeyLocator().getName();
+      if (!data.getSignature().hasKeyLocator())
+        return false;
+
+      const KeyLocator& keyLocator = data.getSignature().getKeyLocator();
+      if (keyLocator.getType() != KeyLocator::KeyLocator_Name)
+        return false;
+
+      const Name& signerName = keyLocator.getName();
       return m_signerRegex->match(signerName);
     }
   catch (Tlv::Error& e)