diff --git a/Cargo.toml b/Cargo.toml
index c2fa9b8..863b009 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -32,7 +32,7 @@ hyper-util = "0.1.7"
 hyper-rustls = { version = "0.27", features = ["http2"] }
 detee-sgx = { git = "ssh://git@gitea.detee.cloud/SGX/detee-sgx", branch = "hacker-challenge", features = ["tonic", "occlum", "sealing"] }
 
-
+once_cell = "1.20.2"
 env_logger = "0.11"
 
 [build-dependencies]
diff --git a/src/persistence.rs b/src/persistence.rs
index 60d937e..59f26dd 100644
--- a/src/persistence.rs
+++ b/src/persistence.rs
@@ -4,11 +4,15 @@ use detee_sgx::SgxError;
 use serde::{Deserialize, Serialize};
 use serde_with::{base64::Base64, serde_as};
 use std::io::Write;
-
+use once_cell::sync::Lazy;
+use std::sync::Mutex;
 pub struct Logfile {}
 
+static LOG_MUTEX: Lazy<Mutex<()>> = Lazy::new(|| Mutex::new(()));
+
 impl Logfile {
     pub fn append(path: &str, msg: &str) -> Result<(), Box<dyn std::error::Error>> {
+        let _lock = LOG_MUTEX.lock();
         let mut file = std::fs::OpenOptions::new().create(true).append(true).open(path)?;
         file.write_all(msg.as_bytes())?;
         Ok(())