diff --git a/include/polarssl/bignum.h b/include/polarssl/bignum.h
index 092e185d5..9cf61a3fc 100644
--- a/include/polarssl/bignum.h
+++ b/include/polarssl/bignum.h
@@ -36,6 +36,7 @@
 #include <basetsd.h>
 typedef  INT16  int16_t;
 typedef UINT16 uint16_t;
+typedef  INT32  int32_t;
 typedef UINT32 uint32_t;
 typedef UINT64 uint64_t;
 #else