diff --git a/core/RInt.hh b/core/RInt.hh
index cc99d73866214891d2a29c20648b7b810c46c804..bbd0e313235f12db36e364d94d8179be59cfe44a 100644
--- a/core/RInt.hh
+++ b/core/RInt.hh
@@ -14,7 +14,8 @@
 #ifndef RInt_HH
 #define RInt_HH
 
-#include <openssl/ossl_typ.h>
+struct bignum_st;
+typedef bignum_st BIGNUM;
 
 typedef int RInt;