diff --git a/include/polarssl/x509write.h b/include/polarssl/x509write.h
index 8ce3d86..9d43efb 100644
--- a/include/polarssl/x509write.h
+++ b/include/polarssl/x509write.h
@@ -41,6 +41,6 @@
 int x509_write_pubkey_der( unsigned char *buf, size_t size, rsa_context *rsa );
 int x509_write_key_der( unsigned char *buf, size_t size, rsa_context *rsa );
 int x509_write_cert_req( unsigned char *buf, size_t size, rsa_context *rsa,
-                         x509_req_name *req_name, int hash_id );
+                         x509_req_name *req_name, md_type_t md_alg );
 
 #endif /* POLARSSL_X509_WRITE_H */