diff --git a/src/user.ts b/src/user.ts
index 905b1c9..25da344 100644
--- a/src/user.ts
+++ b/src/user.ts
@@ -122,8 +122,10 @@ export default class User {
         const privateKeyStr = privateKey;
 
         try {
-          fs.writeFileSync(this.getUserPublicKeyPath(), publicKeyStr);
-          fs.writeFileSync(this.getUserPrivateKeyPath(), privateKeyStr);
+          await fs.writeFileSync(this.getUserPublicKeyPath(), publicKeyStr);
+          await fs.writeFileSync(this.getUserPrivateKeyPath(), privateKeyStr);
+          // limit the permission of private key to prevent that the private key not works
+          await fs.chmodSync(this.getUserPrivateKeyPath(), 0o600)
         } catch(error) {
           console.error("Failed to write public/private key into the default ssh public/key file: ", error);
         }