如何在C#中存储文件或文本的数字签名？

using System;
using System.IO;
using System.Security.Cryptography;

public class DigitalSignature
{
    public static void Main()
    {
        string filePath = "path/to/file.txt";
        string privateKeyPath = "path/to/private_key.pem";
        string publicKeyPath = "path/to/public_key.pem";

        // 读取文件内容
        string fileContent = File.ReadAllText(filePath);

        // 创建数字签名
        byte[] signature = CreateDigitalSignature(fileContent, privateKeyPath);

        // 存储数字签名到文件
        string signatureFilePath = "path/to/signature.txt";
        File.WriteAllBytes(signatureFilePath, signature);

        // 验证数字签名
        bool isSignatureValid = VerifyDigitalSignature(fileContent, signatureFilePath, publicKeyPath);

        Console.WriteLine("数字签名验证结果: " + isSignatureValid);
    }

    // 创建数字签名
    public static byte[] CreateDigitalSignature(string data, string privateKeyPath)
    {
        byte[] dataBytes = System.Text.Encoding.UTF8.GetBytes(data);

        using (var rsa = new RSACryptoServiceProvider())
        {
            // 从私钥文件中加载私钥
            string privateKey = File.ReadAllText(privateKeyPath);
            rsa.FromXmlString(privateKey);

            // 使用SHA256算法计算哈希值
            byte[] hash = new SHA256Managed().ComputeHash(dataBytes);

            // 对哈希值进行签名
            byte[] signature = rsa.SignHash(hash, CryptoConfig.MapNameToOID("SHA256"));

            return signature;
        }
    }

    // 验证数字签名
    public static bool VerifyDigitalSignature(string data, string signatureFilePath, string publicKeyPath)
    {
        byte[] dataBytes = System.Text.Encoding.UTF8.GetBytes(data);
        byte[] signature = File.ReadAllBytes(signatureFilePath);

        using (var rsa = new RSACryptoServiceProvider())
        {
            // 从公钥文件中加载公钥
            string publicKey = File.ReadAllText(publicKeyPath);
            rsa.FromXmlString(publicKey);

            // 使用SHA256算法计算哈希值
            byte[] hash = new SHA256Managed().ComputeHash(dataBytes);

            // 验证签名
            bool isSignatureValid = rsa.VerifyHash(hash, CryptoConfig.MapNameToOID("SHA256"), signature);

            return isSignatureValid;
        }
    }
}