diff --git a/vault.go b/vault.go
index 2ff73ab..1109ff4 100644
--- a/vault.go
+++ b/vault.go
@@ -35,8 +35,8 @@ func (v vault) Store(msg string, ttl string) (token string, err error) {
 	}
 
 	// validate duration length
-	if d > 168 * time.Hour{
-		return "", fmt.Errorf("cannot set ttl to more than 7 days %v", err)
+	if d > 168 * time.Hour || d == 0 * time.Hour  {
+		return "", fmt.Errorf("cannot set ttl to infinte or more than 7 days %v", err)
 	}
 
 	t, err := v.createOneTimeToken(ttl)