如何检查文件是否在C#中签名？

using System;
using System.IO;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using System.Security.Cryptography.Pkcs;

public class Program
{
    public static void Main()
    {
        string filePath = "path/to/your/file";
        bool isSigned = CheckFileSignature(filePath);

        if (isSigned)
        {
            Console.WriteLine("文件已签名");
        }
        else
        {
            Console.WriteLine("文件未签名");
        }
    }

    public static bool CheckFileSignature(string filePath)
    {
        try
        {
            byte[] fileContent = File.ReadAllBytes(filePath);
            SignedCms signedCms = new SignedCms();
            signedCms.Decode(fileContent);
            signedCms.CheckSignature(true);
            return true;
        }
        catch (Exception ex)
        {
            Console.WriteLine("Error: " + ex.Message);
            return false;
        }
    }
}