else if (do_mac == TFC_MAC_SIGN) {
if (ctr_mode < TFC_MODE_OCB) skein_final(macresult, &sk);
else skein(macresult, macbits, mackey, macresult, TF_FROM_BITS(macbits));
else if (do_mac == TFC_MAC_SIGN) {
if (ctr_mode < TFC_MODE_OCB) skein_final(macresult, &sk);
else skein(macresult, macbits, mackey, macresult, TF_FROM_BITS(macbits));