基于RSA的数字签名和验证C#源码

【核心代码】

/* 备注：
 * 若要使用公钥系统对消息进行数字签名，发送方先向该消息应用哈希函数以创建消息摘要。
 * 然后，发送方用自己的私钥对消息摘要进行加密，以创建发送方的个人签名。在收到消息和
 * 签名后，接收方使用发送方的公钥解密该签名，以恢复消息摘要，并使用发送方所用的同一
 * 哈希算法对该消息进行哈希运算。如果接收方计算的消息摘要与从发送方收到的消息摘要完
 * 全匹配，则接收方可以假定消息在传输中未被更改。请注意，因为发送方的公钥是公共知识，
 * 所以任何人都可以验证签名。
 */

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

class RSACSPSample
{
    static void Main()
    {
        try
        {

            string str_DataToSign = @"Data to Sign!Data to Sign!Data to Sign!";
            Console.WriteLine("原文："   str_DataToSign);
            Console.WriteLine("长度："   str_DataToSign.Length.ToString());
            Console.WriteLine();

            RSACryptoServiceProvider RSAalg = new RSACryptoServiceProvider();

            string str_Private_Key = Convert.ToBase64String( RSAalg.ExportCspBlob(true) );
            string str_Public_Key = Convert.ToBase64String( RSAalg.ExportCspBlob(false) );
            Console.WriteLine("公钥："   str_Public_Key);
            Console.WriteLine();
            Console.WriteLine("私钥："   str_Private_Key);
            Console.WriteLine();

            string str_SignedData = HashAndSign(str_DataToSign, str_Private_Key);// Hash and sign the data.
            Console.WriteLine("签名数据："   str_SignedData);
            Console.WriteLine();

            if (VerifySignedHash(str_DataToSign, str_SignedData, str_Public_Key))
            {
                Console.WriteLine("验证签名OK.");
            }
            else
            {
                Console.WriteLine("签名不匹配!");
            }
            Console.WriteLine();

        }
        catch (ArgumentNullException)
        {
            Console.WriteLine("The data was not signed or verified");

        }
    }

    //对数据签名
    public static string HashAndSign(string str_DataToSign, string str_Private_Key)
    {
        ASCIIEncoding ByteConverter = new ASCIIEncoding();
        byte[] DataToSign = ByteConverter.GetBytes(str_DataToSign);
        try
        {
            RSACryptoServiceProvider RSAalg = new RSACryptoServiceProvider();
            RSAalg.ImportCspBlob( Convert.FromBase64String(str_Private_Key) );
            byte[] signedData = RSAalg.SignData(DataToSign, new SHA1CryptoServiceProvider());
            string str_SignedData = Convert.ToBase64String(signedData);
            return str_SignedData;
        }
        catch (CryptographicException e)
        {
            Console.WriteLine(e.Message);
            return null;
        }
    }

    //验证签名
    public static bool VerifySignedHash(string str_DataToVerify, string str_SignedData, string str_Public_Key)
    {
        byte[] SignedData = Convert.FromBase64String(str_SignedData);

        ASCIIEncoding ByteConverter = new ASCIIEncoding();
        byte[] DataToVerify = ByteConverter.GetBytes(str_DataToVerify);
        try
        {
            RSACryptoServiceProvider RSAalg = new RSACryptoServiceProvider();
            RSAalg.ImportCspBlob( Convert.FromBase64String(str_Public_Key) );

            return RSAalg.VerifyData(DataToVerify, new SHA1CryptoServiceProvider(), SignedData);

        }
        catch (CryptographicException e)
        {
            Console.WriteLine(e.Message);

            return false;
        }
    }
}