form1.cs

这个是用c#编写的用SHA算法生成报文鉴别码

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.IO;
using System.Security;
using System.Security.Cryptography;

namespace DigestAndSignature
{
    public partial class btnSaveFile : Form
    {
        private string openFileName;
        private string saveFileName;
        private byte[] hashBytes;

        public byte[] HashCreate(string filePath)
        {
            //利用SHA报文算法生成报文鉴别码
            HashAlgorithm hash = HashAlgorithm.Create();
            //读入文件
            FileStream fs = new FileStream(filePath, FileMode.Open);
            //计算hash值
            byte[] hashBytes = hash.ComputeHash(fs);
            fs.Close();
            return hashBytes;
        }

        public bool EncryptFile(byte[] hashBytes, string outPath)
        {   
            try
            {
                //利用RSA算法对报文鉴别码进行数字签名
                RSACryptoServiceProvider rsac = new RSACryptoServiceProvider();
                //打开文件输出流
                FileStream res = new FileStream(outPath, FileMode.Create, FileAccess.Write);
                hashBytes = rsac.Encrypt(hashBytes, false);
                res.Write(hashBytes, 0, hashBytes.Length);
                res.Close();
                //保存密钥到文件
                StreamWriter sw = new StreamWriter("RSA.key");
                sw.Write(rsac.ToXmlString(true));
                sw.Close();
                return true;
            }
            catch (System.Exception e)
            {
                return false;
            }
        }

        public btnSaveFile()
        {
            InitializeComponent();
        }

        private void btnOpenFile_Click(object sender, EventArgs e)
        {
            openFileDlg.ShowDialog();
        }

        private void button2_Click(object sender, EventArgs e)
        {
            saveFileDlg.ShowDialog();
        }

        private void openFileDlg_FileOk(object sender, CancelEventArgs e)
        {
            txtOpenFile.Text = openFileDlg.FileName;
            openFileName = txtOpenFile.Text;
        }

        private void saveFileDlg_FileOk(object sender, CancelEventArgs e)
        {
            txtSaveFile.Text = saveFileDlg.FileName;
            saveFileName = txtSaveFile.Text;
        }

        private void btnSHA_Click(object sender, EventArgs e)
        {
            hashBytes=HashCreate(openFileName);
            if(hashBytes.Length>0)
            {
                MessageBox.Show("报文鉴别码是:"+BitConverter.ToString(hashBytes));
            }
            else
            {
                MessageBox.Show("error!");
            }
        }

        private void btnRSA_Click(object sender, EventArgs e)
        {
            if(txtSaveFile.Text=="")
            {
                MessageBox.Show("请输入保存的文件名!");
                return;
            }
            if (EncryptFile(hashBytes,txtSaveFile.Text))
            {
                MessageBox.Show("success!");
            }
            else
            {
                MessageBox.Show("error!");
            }
        }
    }
}