diff --git a/sys/netinet/ip_carp.c b/sys/netinet/ip_carp.c
--- a/sys/netinet/ip_carp.c
+++ b/sys/netinet/ip_carp.c
@@ -720,6 +720,9 @@
 	if_detach(ifp);
 
 	KASSERT(sc->sc_naddrs == 0, ("certain inet address is still active"));
+	bzero(sc->sc_key, sizeof(sc->sc_key));
+	bzero(sc->sc_pad, sizeof(sc->sc_pad));
+	bzero(&sc->sc_sha1, sizeof(sc->sc_sha1));
 	kfree(sc, M_CARP);
 
 	return 0;