diff --git a/Library/Engine.cs b/Library/Engine.cs
index 9f0782d..ebabb81 100644
--- a/Library/Engine.cs
+++ b/Library/Engine.cs
@@ -135,14 +135,15 @@ public class Engine
 		{
 			fstream = new FileStream(file_path, FileMode.Open);
 			var signature = Cryptography.SignDataByPrivateCert(fstream.ToString(), private_key_path.GetPrivateCert(pass));
-			if (Cryptography.VerifySignedDataByCertIssuer(signature, open_key_path.GetPublicCert(), out var data))
+			fstream.Close();
+			if (!Cryptography.VerifySignedDataByCertIssuer(signature, open_key_path.GetPublicCert(), out var data))
 			{
-				if (data != null)
-					return false;
+
+				return true;
 			}
 			else
 			{
-				return true;
+				return false;
 			}
 		}
 		catch (Exception ex)