diff --git a/posts/2023-08-23-real-world-crypto.md b/posts/2023-08-23-real-world-crypto.md
index 8e5bda0..c7a12d4 100644
--- a/posts/2023-08-23-real-world-crypto.md
+++ b/posts/2023-08-23-real-world-crypto.md
@@ -17,7 +17,7 @@ authentication tag. **HMAC** is MAC using hash.
 - B double check message with MAC (generate from receive message and B key).
 - A and B use same key.
 
-```mermald
+```mermaid
 sequenceDiagram
     participant alice
     participant bob