+struct openpgp_signedpacket_list *find_signed_packet(
+ struct openpgp_signedpacket_list *packet_list,
+ struct openpgp_packet *packet);
+
+/**
+ * merge_packet_sigs - Takes 2 signed packets and merges their sigs.
+ * @old: The old signed packet.
+ * @new: The new signed packet.
+ *
+ * Takes 2 signed packet list structures and the sigs of the packets on
+ * the head of these structures. These packets must both be the same and
+ * the fully merged structure is returned in old and the minimal
+ * difference to get from old to new in new.
+ */
+int merge_packet_sigs(struct openpgp_signedpacket_list *old,
+ struct openpgp_signedpacket_list *new);