diff --git a/nip70/nip70.go b/nip70/nip70.go
new file mode 100644
index 0000000..4cb0755
--- /dev/null
+++ b/nip70/nip70.go
@@ -0,0 +1,12 @@
+package nip70
+
+import "github.com/nbd-wtf/go-nostr"
+
+func IsProtected(event *nostr.Event) bool {
+	for _, tag := range event.Tags {
+		if len(tag) == 1 && tag[0] == "-" {
+			return true
+		}
+	}
+	return false
+}