added lib dir

lib/md5.h

@@ -0,0 +1,10 @@
+#ifndef _MD5_H_
+#define _MD5_H_
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+
+void md5(const uint8_t *initial_msg, size_t initial_len, uint8_t *digest);
+
+#endif