diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index d7c47e6..17149c5 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -55,6 +55,7 @@
 #endif
 
 #include "mbedtls/pk.h"
+#include "pk_internal.h"
 #include "common.h"
 
 /* Shorthand for restartable ECC */