diff --git a/src/libWiiPy_NinjaCheetah/commonkey.py b/src/libWiiPy_NinjaCheetah/commonkey.py
new file mode 100644
index 0000000..dc70b3f
--- /dev/null
+++ b/src/libWiiPy_NinjaCheetah/commonkey.py
@@ -0,0 +1,17 @@
+from .shared import hex_string_to_byte_array
+
+
+class CommonKey:
+    def __init__(self):
+        self.default_key = "ebe42a225e8593e448d9c5457381aaf7"
+        self.korean_key = "63b82bb4f4614e2e13f2fefbba4c9b7e"
+        self.vwii_key = "30bfc76e7c19afbb23163330ced7c28d"
+
+    def get_default_key(self):
+        return hex_string_to_byte_array(self.default_key)
+
+    def get_korean_key(self):
+        return hex_string_to_byte_array(self.korean_key)
+
+    def get_vwii_key(self):
+        return hex_string_to_byte_array(self.vwii_key)
diff --git a/src/libWiiPy_NinjaCheetah/example.py b/src/libWiiPy_NinjaCheetah/example.py
deleted file mode 100644
index 1ee9ec6..0000000
--- a/src/libWiiPy_NinjaCheetah/example.py
+++ /dev/null
@@ -1,2 +0,0 @@
-def add_one(number):
-    return number + 1
\ No newline at end of file
diff --git a/src/libWiiPy_NinjaCheetah/shared.py b/src/libWiiPy_NinjaCheetah/shared.py
new file mode 100644
index 0000000..7172771
--- /dev/null
+++ b/src/libWiiPy_NinjaCheetah/shared.py
@@ -0,0 +1,9 @@
+from typing import List
+from binascii import unhexlify
+
+
+def hex_string_to_byte_array(hex_string: str) -> List[int]:
+    byte_string = unhexlify(hex_string)
+    byte_array = list(byte_string)
+
+    return byte_array