diff --git md5.h md5.h

index d8b96df..86103da 100644

--- md5.h

+++ md5.h

@@ -124,6 +124,13 @@ private:

 #include CRYPTOPP_INCLUDE_MD5

 #endif

+#if (CRYPTOPP_VERSION >= 600) && (__cplusplus >= 201103L)

+  using byte = CryptoPP::byte;

+#else

+  typedef unsigned char byte;

+#endif

+

+

 class MD5 {

 public:

@@ -151,4 +158,4 @@ private:

 #endif //DO_NOT_USE_CRYPTOPP_MD5

-#endif //MD5_H

\ No newline at end of file

+#endif //MD5_H