update

1 files changed, 6 insertions, 0 deletions

diff --git a/README.md b/README.md
index 01750e2..5b1a044 100644
--- a/README.md
+++ b/README.md
@@ -38,8 +38,14 @@ swiftc -o keychain-fingerprint main.swift -framework LocalAuthentication -framew
 
 # Install (optional)
 sudo cp keychain-fingerprint /usr/local/bin/
+
+# IMPORTANT: Set root ownership (security)
+sudo chown root:wheel keychain-fingerprint
+sudo chmod 755 keychain-fingerprint
 ```
 
+> ⚠️ **Security Note**: The binary must be owned by root with execute-only permission for regular users. This prevents malicious code injection into a tool that accesses Keychain.
+
 ## Usage
 
 ```bash