c# -对文件进行数字签名

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

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
        string signature = CreateSignature(fileContent, privateKeyPath);

        // 验证数字签名
        bool isValid = VerifySignature(fileContent, signature, publicKeyPath);

        Console.WriteLine("数字签名是否有效: " + isValid);
    }

    // 创建数字签名
    public static string CreateSignature(string data, string privateKeyPath)
    {
        byte[] privateKeyBytes = File.ReadAllBytes(privateKeyPath);

        using (var rsa = RSA.Create())
        {
            rsa.ImportRSAPrivateKey(privateKeyBytes, out _);

            byte[] dataBytes = Encoding.UTF8.GetBytes(data);
            byte[] signatureBytes = rsa.SignData(dataBytes, HashAlgorithmName.SHA256, RSASignaturePadding.Pkcs1);

            return Convert.ToBase64String(signatureBytes);
        }
    }

    // 验证数字签名
    public static bool VerifySignature(string data, string signature, string publicKeyPath)
    {
        byte[] publicKeyBytes = File.ReadAllBytes(publicKeyPath);

        using (var rsa = RSA.Create())
        {
            rsa.ImportRSAPublicKey(publicKeyBytes, out _);

            byte[] dataBytes = Encoding.UTF8.GetBytes(data);
            byte[] signatureBytes = Convert.FromBase64String(signature);

            return rsa.VerifyData(dataBytes, signatureBytes, HashAlgorithmName.SHA256, RSASignaturePadding.Pkcs1);
        }
    }
}