diff --git a/library/x509_internal.h b/library/x509_internal.h
index e1be393..15e097a 100644
--- a/library/x509_internal.h
+++ b/library/x509_internal.h
@@ -15,7 +15,7 @@
 
 #include "mbedtls/x509.h"
 #include "mbedtls/asn1.h"
-#include "mbedtls/pk.h"
+#include "pk_internal.h"
 
 #if defined(MBEDTLS_RSA_C)
 #include "mbedtls/rsa.h"