diff --git a/include/polarssl/md5.h b/include/polarssl/md5.h
index 936e9c9..3167860 100644
--- a/include/polarssl/md5.h
+++ b/include/polarssl/md5.h
@@ -147,6 +147,9 @@
  */
 int md5_self_test( int verbose );
 
+/* Internal use */
+void md5_process( md5_context *ctx, const unsigned char data[64] );
+
 #ifdef __cplusplus
 }
 #endif