diff --git a/config/security.go b/config/security.go
index 0aa698924854ea9233b24b29df91a7ab24ffcdfa..2798fda85f0a8e604d6d8c565559a6ada333580b 100644
--- a/config/security.go
+++ b/config/security.go
@@ -61,7 +61,7 @@ func makeSecurityTransport(h host.Host, tpts []MsSecC) (security.Transport, erro
 		if _, ok := transportSet[tptC.ID]; ok {
 			return nil, fmt.Errorf("duplicate security transport: %s", tptC.ID)
 		}
-		transportSet[tptC.ID] = tptC
+		transportSet[tptC.ID] = struct{}{}
 	}
 	for _, tptC := range tpts {
 		tpt, err := tptC.SecC(h)