diff --git a/common/protocol/headers.proto b/common/protocol/headers.proto
index 943d7d6f7..725b3cc5d 100644
--- a/common/protocol/headers.proto
+++ b/common/protocol/headers.proto
@@ -13,6 +13,7 @@ enum SecurityType {
   AES128_GCM = 3;
   CHACHA20_POLY1305 = 4;
   NONE = 5;
+  ZERO = 6;
 }
 
 message SecurityConfig {