diff --git a/server/test_ctypes.py b/server/test_ctypes.py
new file mode 100755
index 0000000..20f2bd9
--- /dev/null
+++ b/server/test_ctypes.py
@@ -0,0 +1,31 @@
+#!/usr/bin/env python3
+# -*-coding:UTF-8 -*
+
+from ctypes import *
+
+class D4Header(Structure):
+    _fields_ = [
+        ("version", c_uint8),
+        ("type", c_uint8),
+        #("uuid", c_uint128),
+        ("uuid", c_uint64),
+        ("timestamp", c_uint64),
+        #("hmac", c_uint256),
+        ("hmac", c_uint64),
+        ("size", c_uint32),
+        ]
+
+def pack(ctype_instance):
+    return string_at(byref(ctype_instance), sizeof(ctype_instance))
+
+def unpack(ctype, buffer):
+    c_str = create_string_buffer(buffer)
+    return cast(pointer(c_str), POINTER(ctype)).contents
+
+if __name__ == '__main__':
+    d4h = D4Header(1,1,88888,1543398024,233243445342,342)
+    print(d4h.version)
+    buffer = pack(d4h)
+    print(buffer)
+    d = unpack(D4Header, buffer)
+    assert(d4h.version == d.version)