changed.对启动器重构的尝试

LanMountainDesktop.Launcher/Update/UpdateSignatureVerifier.cs

@@ -0,0 +1,41 @@
+using System.Security.Cryptography;
+
+namespace LanMountainDesktop.Launcher.Update;
+
+internal sealed class UpdateSignatureVerifier(UpdateEnginePaths paths)
+{
+    public (bool Success, string Message) Verify(string payloadPath, string signaturePath, string signatureName)
+    {
+        if (!File.Exists(signaturePath))
+        {
+            return (false, $"Missing {signatureName}.");
+        }
+
+        if (!File.Exists(paths.PublicKeyPath))
+        {
+            return (false, $"Missing public key: {paths.PublicKeyPath}");
+        }
+
+        var payloadBytes = File.ReadAllBytes(payloadPath);
+        var signatureBase64 = File.ReadAllText(signaturePath).Trim();
+        if (string.IsNullOrWhiteSpace(signatureBase64))
+        {
+            return (false, "Signature is empty.");
+        }
+
+        byte[] signature;
+        try
+        {
+            signature = Convert.FromBase64String(signatureBase64);
+        }
+        catch (FormatException)
+        {
+            return (false, "Signature is not valid base64.");
+        }
+
+        using var rsa = RSA.Create();
+        rsa.ImportFromPem(File.ReadAllText(paths.PublicKeyPath));
+        var isValid = rsa.VerifyData(payloadBytes, signature, HashAlgorithmName.SHA256, RSASignaturePadding.Pkcs1);
+        return isValid ? (true, "ok") : (false, "Signature verification failed.");
+    }
+}