diff --git a/commands.hpp b/commands.hpp
index ce68129..ccce978 100644
--- a/commands.hpp
+++ b/commands.hpp
@@ -28,8 +28,8 @@
  * as that of the covered work.
  */
 
-#ifndef _COMMANDS_H
-#define _COMMANDS_H
+#ifndef GIT_CRYPT_COMMANDS_HPP
+#define GIT_CRYPT_COMMANDS_HPP
 
 
 void clean (const char* keyfile);
diff --git a/crypto.hpp b/crypto.hpp
index e8166e2..6bde6ab 100644
--- a/crypto.hpp
+++ b/crypto.hpp
@@ -28,8 +28,8 @@
  * as that of the covered work.
  */
 
-#ifndef _CRYPTO_H
-#define _CRYPTO_H
+#ifndef GIT_CRYPT_CRYPTO_HPP
+#define GIT_CRYPT_CRYPTO_HPP
 
 #include <openssl/aes.h>
 #include <openssl/hmac.h>
diff --git a/util.hpp b/util.hpp
index aa76982..18ea199 100644
--- a/util.hpp
+++ b/util.hpp
@@ -28,8 +28,8 @@
  * as that of the covered work.
  */
 
-#ifndef _UTIL_H
-#define _UTIL_H
+#ifndef GIT_CRYPT_UTIL_HPP
+#define GIT_CRYPT_UTIL_HPP
 
 #include <string>
 #include <ios>