diff --git a/libp2p/security/secio/exceptions.py b/libp2p/security/secio/exceptions.py
index 892f63d..c03fda4 100644
--- a/libp2p/security/secio/exceptions.py
+++ b/libp2p/security/secio/exceptions.py
@@ -24,3 +24,7 @@ class InvalidSignatureOnExchange(SecioException):
 
 class IncompatibleChoices(SecioException):
     pass
+
+
+class InconsistentNonce(SecioException):
+    pass