diff --git a/ssl/internal.h b/ssl/internal.h
index f19a265..a1600f8 100644
--- a/ssl/internal.h
+++ b/ssl/internal.h
@@ -346,6 +346,10 @@
 
 /* Private key operations. */
 
+/* ssl_has_private_key returns one if |ssl| has a private key
+ * configured and zero otherwise. */
+int ssl_has_private_key(SSL *ssl);
+
 /* ssl_private_key_* call the corresponding function on the
  * |SSL_PRIVATE_KEY_METHOD| for |ssl|, if configured. Otherwise, they implement
  * the operation with |EVP_PKEY|. */