diff --git a/src/NLPacketCodec.hpp b/src/NLPacketCodec.hpp
index 0c66328..119b0d1 100644
--- a/src/NLPacketCodec.hpp
+++ b/src/NLPacketCodec.hpp
@@ -102,6 +102,10 @@ public:
     void setSequenceNumber(SequenceNumber seq);
     void setSourceID(LocalID id);
     
+    // Protocol version signature
+    static std::vector<uint8_t> computeProtocolVersionSignature();
+    static uint8_t versionForPacketType(PacketType type);
+    
 private:
     void writeHeader();