diff --git a/README.md b/README.md
index 8042ef4..c422501 100644
--- a/README.md
+++ b/README.md
@@ -26,6 +26,7 @@ Flags:
 ```
 
 # Versions:
+- V5 - Add support for linux 
 - V4 - Add select save folder
 - V3 - Add username to LoginInfo
 - V2 - Remove string size limit
diff --git a/include/func.hpp b/include/func.hpp
index e4cef6f..ad84348 100644
--- a/include/func.hpp
+++ b/include/func.hpp
@@ -21,6 +21,7 @@ struct LoginInfoPointer
 
 struct Index
 {
+	uint32_t magic;
 	uint32_t count;
 	uint32_t offset;
 };
diff --git a/main.cpp b/main.cpp
index e89075f..0f4600c 100644
--- a/main.cpp
+++ b/main.cpp
@@ -1,5 +1,6 @@
 #include <iostream>
 #include <fstream>
+#include <cstring>
 
 #include "sys.hpp"
 #include "buffer.hpp"
@@ -85,10 +86,18 @@ int main(int argc, char **argv)
 	if (decrypted_buffer.taken < sizeof(Index))
 	{
 		Index index = {0};
+		std::memcpy(&index.magic, ".bin", 4);
 		index.offset = sizeof(Index);
 		decrypted_buffer.add_end((uint8_t *)&index, sizeof(Index));
 	}
 
+	// check for magic num to see if file is decrypted correcly
+	if (std::memcmp(decrypted_buffer.buffer, ".bin", 4))
+	{
+		printf("Worong password!!");
+		return 1;
+	}
+
 	std::optional<LoginInfoPointer> login_info;
 
 	switch (args)