diff --git a/state/sign.go b/state/sign.go
index aaf1a2d..8316b52 100644
--- a/state/sign.go
+++ b/state/sign.go
@@ -27,3 +27,10 @@ func (m HealthRequest) SignedData() ([]byte, error) {
 func (m DumpRequest) SignedData() ([]byte, error) {
 	return make([]byte, 0), nil
 }
+
+// SignedData returns payload bytes of the request.
+//
+// Always returns an empty slice.
+func (m DumpVarsRequest) SignedData() ([]byte, error) {
+	return make([]byte, 0), nil
+}
diff --git a/state/sign_test.go b/state/sign_test.go
index cc525bc..dd55d21 100644
--- a/state/sign_test.go
+++ b/state/sign_test.go
@@ -42,6 +42,11 @@ func TestRequestSign(t *testing.T) {
 				return new(DumpRequest)
 			},
 		},
+		{ // DumpVarsRequest
+			constructor: func() sigType {
+				return new(DumpVarsRequest)
+			},
+		},
 	}
 
 	for _, item := range items {