--- include/types.h
+++ include/types.h
@@ -7,21 +7,22 @@
 #define BOTAN_TYPES_H__
 
 #include <botan/build.h>
+#include <stdint.h>
 
 namespace Botan {
 
-typedef unsigned char byte;
-typedef unsigned short u16bit;
-typedef unsigned int u32bit;
+typedef uint8_t byte;
+typedef uint16_t u16bit;
+typedef uint32_t u32bit;
 
-typedef signed int s32bit;
+typedef int32_t s32bit;
 
 #if defined(_MSC_VER) || defined(__BORLANDC__)
    typedef unsigned __int64 u64bit;
 #elif defined(__KCC)
    typedef unsigned __long_long u64bit;
 #elif defined(__GNUG__)
-   __extension__ typedef unsigned long long u64bit;
+   __extension__ typedef uint64_t u64bit;
 #else
    typedef unsigned long long u64bit;
 #endif