add no-op authenticator

transport/internet/authenticator.go

@@ -85,3 +85,25 @@ func (this *AuthenticatorChain) Seal(payload *alloc.Buffer) {
 		auth.Seal(payload)
 	}
 }
+
+type NoOpAuthenticator struct{}
+
+func (this NoOpAuthenticator) Overhead() int {
+	return 0
+}
+func (this NoOpAuthenticator) Open(payload *alloc.Buffer) bool {
+	return true
+}
+func (this NoOpAuthenticator) Seal(payload *alloc.Buffer) {}
+
+type NoOpAuthenticatorFactory struct{}
+
+func (this NoOpAuthenticatorFactory) Create(config AuthenticatorConfig) Authenticator {
+	return NoOpAuthenticator{}
+}
+
+type NoOpAuthenticatorConfig struct{}
+
+func init() {
+	RegisterAuthenticator("none", NoOpAuthenticatorFactory{}, func() interface{} { return NoOpAuthenticatorConfig{} })
+}