diff --git a/src/client-module.hpp b/src/client-module.hpp
index 806c5bc..b3655ef 100644
--- a/src/client-module.hpp
+++ b/src/client-module.hpp
@@ -153,7 +153,7 @@
   time::system_clock::TimePoint m_freshBefore;
 
   ECDHState m_ecdh;
-  uint8_t m_aesKey[32] = {0};
+  uint8_t m_aesKey[16] = {0};
 };
 
 } // namespace ndncert