diff --git a/include/polarssl/x509.h b/include/polarssl/x509.h
index 17d99af..ed02ad9 100644
--- a/include/polarssl/x509.h
+++ b/include/polarssl/x509.h
@@ -27,10 +27,14 @@
 #ifndef POLARSSL_X509_H
 #define POLARSSL_X509_H
 
+#include "config.h"
+
+#if defined(POLARSSL_X509_PARSE_C) || defined(POLARSSL_X509_WRITE_C)
 #include "asn1.h"
 #include "rsa.h"
 #include "dhm.h"
 #include "md.h"
+#include "pk.h"
 
 /** 
  * \addtogroup x509_module
@@ -134,12 +138,6 @@
 #define X509_FORMAT_DER                 1
 #define X509_FORMAT_PEM                 2
 
-typedef enum {
-    POLARSSL_PK_NONE=0,
-    POLARSSL_PK_RSA,
-    POLARSSL_PK_ECDSA,
-} pk_type_t;
-
 /** 
  * \addtogroup x509_module
  * \{ */
@@ -668,4 +666,5 @@
 }
 #endif
 
+#endif /* POLARSSL_X509_PARSE_C || POLARSSL_X509_WRITE_C */
 #endif /* x509.h */