简单加密算法在C#中的实现

加密是指通过某种特殊的方法，更改已有信息的内容，是的未授权的用户即使得到了加密的信息，如果没有正确的解密算法，
那么也无法得到信息的内容。

方法一：
    //须添加对System.Web的引用
    using System.Web.Security; 

    ... 

    /// <summary>
    /// SHA1加密字符串
    /// </summary>
    /// <param name="source">源字符串</param>
    /// <returns>加密后的字符串</returns>
    public string SHA1(string source)
    {
        return FormsAuthentication.HashPasswordForStoringInConfigFile(source, "SHA1");
    } 

    /// <summary>
    /// MD5加密字符串
    /// </summary>
    /// <param name="source">源字符串</param>
    /// <returns>加密后的字符串</returns>
    public string MD5(string source)
    {
        return FormsAuthentication.HashPasswordForStoringInConfigFile(source, "MD5");;
    }
 方法二(可逆加密解密)：
    using System.Security.Cryptography; 

    ... 

    public string Encode(string data)
    {
        byte[] byKey = System.Text.ASCIIEncoding.ASCII.GetBytes(KEY_64);
        byte[] byIV = System.Text.ASCIIEncoding.ASCII.GetBytes(IV_64); 

        DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();
        int i = cryptoProvider.KeySize;
        MemoryStream ms = new MemoryStream();
        CryptoStream cst = new CryptoStream(ms, cryptoProvider.CreateEncryptor(byKey, byIV), CryptoStreamMode.Write); 

        StreamWriter sw = new StreamWriter(cst);
        sw.Write(data);
        sw.Flush();
        cst.FlushFinalBlock();
        sw.Flush();
        return Convert.ToBase64String(ms.GetBuffer(), , (int)ms.Length); 

    } 

    public string Decode(string data)
    {
        byte[] byKey = System.Text.ASCIIEncoding.ASCII.GetBytes(KEY_64);
        byte[] byIV = System.Text.ASCIIEncoding.ASCII.GetBytes(IV_64); 

        byte[] byEnc;
        try
        {
            byEnc = Convert.FromBase64String(data);
        }
        catch
        {
            return null;
        } 

        DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();
        MemoryStream ms = new MemoryStream(byEnc);
        CryptoStream cst = new CryptoStream(ms, cryptoProvider.CreateDecryptor(byKey, byIV), CryptoStreamMode.Read);
        StreamReader sr = new StreamReader(cst);
        return sr.ReadToEnd();
    }
方法三(MD5不可逆)：
    using System.Security.Cryptography; 

    ... 

    //MD5不可逆加密 

    //32位加密 

    public string GetMD5_32(string s, string _input_charset)
    {
        MD5 md5 = new MD5CryptoServiceProvider();
        byte[] t = md5.ComputeHash(Encoding.GetEncoding(_input_charset).GetBytes(s));
        StringBuilder sb = new StringBuilder();
        for (int i = ; i < t.Length; i++)
        {
            sb.Append(t[i].ToString("x").PadLeft(, ''));
        }
        return sb.ToString();
    } 

    //16位加密
    public static string GetMd5_16(string ConvertString)
    {
        MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();
        string t2 = BitConverter.ToString(md5.ComputeHash(UTF8Encoding.Default.GetBytes(ConvertString)), , );
        t2 = t2.Replace("-", "");
        return t2;
    }
方法四(对称加密)：
    using System.IO;
    using System.Security.Cryptography; 

    ... 

    private SymmetricAlgorithm mobjCryptoService;
    private string Key;
    /// <summary>
    /// 对称加密类的构造函数
    /// </summary>
    public SymmetricMethod()
    {
        mobjCryptoService = new RijndaelManaged();
        Key = "Guz(%&hj7x89H$yuBI0456FtmaT5&fvHUFCy76*h%(HilJ$lhj!y6&(*jkP87jH7";
    }
    /// <summary>
    /// 获得密钥
    /// </summary>
    /// <returns>密钥</returns>
    private byte[] GetLegalKey()
    {
        string sTemp = Key;
        mobjCryptoService.GenerateKey();
        byte[] bytTemp = mobjCryptoService.Key;
        int KeyLength = bytTemp.Length;
        if (sTemp.Length > KeyLength)
            sTemp = sTemp.Substring(, KeyLength);
        else if (sTemp.Length < KeyLength)
            sTemp = sTemp.PadRight(KeyLength, ' ');
        return ASCIIEncoding.ASCII.GetBytes(sTemp);
    }
    /// <summary>
    /// 获得初始向量IV
    /// </summary>
    /// <returns>初试向量IV</returns>
    private byte[] GetLegalIV()
    {
        string sTemp = "E4ghj*Ghg7!rNIfb&95GUY86GfghUb#er57HBh(u%g6HJ($jhWk7&!hg4ui%$hjk";
        mobjCryptoService.GenerateIV();
        byte[] bytTemp = mobjCryptoService.IV;
        int IVLength = bytTemp.Length;
        if (sTemp.Length > IVLength)
            sTemp = sTemp.Substring(, IVLength);
        else if (sTemp.Length < IVLength)
            sTemp = sTemp.PadRight(IVLength, ' ');
        return ASCIIEncoding.ASCII.GetBytes(sTemp);
    }
    /// <summary>
    /// 加密方法
    /// </summary>
    /// <param name="Source">待加密的串</param>
    /// <returns>经过加密的串</returns>
    public string Encrypto(string Source)
    {
        byte[] bytIn = UTF8Encoding.UTF8.GetBytes(Source);
        MemoryStream ms = new MemoryStream();
        mobjCryptoService.Key = GetLegalKey();
        mobjCryptoService.IV = GetLegalIV();
        ICryptoTransform encrypto = mobjCryptoService.CreateEncryptor();
        CryptoStream cs = new CryptoStream(ms, encrypto, CryptoStreamMode.Write);
        cs.Write(bytIn, , bytIn.Length);
        cs.FlushFinalBlock();
        ms.Close();
        byte[] bytOut = ms.ToArray();
        return Convert.ToBase64String(bytOut);
    }
    /// <summary>
    /// 解密方法
    /// </summary>
    /// <param name="Source">待解密的串</param>
    /// <returns>经过解密的串</returns>
    public string Decrypto(string Source)
    {
        byte[] bytIn = Convert.FromBase64String(Source);
        MemoryStream ms = new MemoryStream(bytIn, , bytIn.Length);
        mobjCryptoService.Key = GetLegalKey();
        mobjCryptoService.IV = GetLegalIV();
        ICryptoTransform encrypto = mobjCryptoService.CreateDecryptor();
        CryptoStream cs = new CryptoStream(ms, encrypto, CryptoStreamMode.Read);
        StreamReader sr = new StreamReader(cs);
        return sr.ReadToEnd();
    }
方法五：
    using System.IO;
    using System.Security.Cryptography;
    using System.Text; 

    ... 

    //默认密钥向量
    private static byte[] Keys = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };
    /// <summary>
    /// DES加密字符串
    /// </summary>
    /// <param name="encryptString">待加密的字符串</param>
    /// <param name="encryptKey">加密密钥,要求为8位</param>
    /// <returns>加密成功返回加密后的字符串，失败返回源串</returns>
    public static string EncryptDES(string encryptString, string encryptKey)
    {
        try
        {
            byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey.Substring(, ));
            byte[] rgbIV = Keys;
            byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);
            DESCryptoServiceProvider dCSP = new DESCryptoServiceProvider();
            MemoryStream mStream = new MemoryStream();
            CryptoStream cStream = new CryptoStream(mStream, dCSP.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
            cStream.Write(inputByteArray, , inputByteArray.Length);
            cStream.FlushFinalBlock();
            return Convert.ToBase64String(mStream.ToArray());
        }
        catch
        {
            return encryptString;
        }
    } 

    /// <summary>
    /// DES解密字符串
    /// </summary>
    /// <param name="decryptString">待解密的字符串</param>
    /// <param name="decryptKey">解密密钥,要求为8位,和加密密钥相同</param>
    /// <returns>解密成功返回解密后的字符串，失败返源串</returns>
    public static string DecryptDES(string decryptString, string decryptKey)
    {
        try
        {
            byte[] rgbKey = Encoding.UTF8.GetBytes(decryptKey);
            byte[] rgbIV = Keys;
            byte[] inputByteArray = Convert.FromBase64String(decryptString);
            DESCryptoServiceProvider DCSP = new DESCryptoServiceProvider();
            MemoryStream mStream = new MemoryStream();
            CryptoStream cStream = new CryptoStream(mStream, DCSP.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
            cStream.Write(inputByteArray, , inputByteArray.Length);
            cStream.FlushFinalBlock();
            return Encoding.UTF8.GetString(mStream.ToArray());
        }
        catch
        {
            return decryptString;
        }
    }
方法六(文件加密)：
    using System.IO;
    using System.Security.Cryptography;
    using System.Text; 

    ... 

    //加密文件
    private static void EncryptData(String inName, String outName, byte[] desKey, byte[] desIV)
    {
        //Create the file streams to handle the input and output files.
        FileStream fin = new FileStream(inName, FileMode.Open, FileAccess.Read);
        FileStream fout = new FileStream(outName, FileMode.OpenOrCreate, FileAccess.Write);
        fout.SetLength(); 

        //Create variables to help with read and write.
        byte[] bin = new byte[]; //This is intermediate storage for the encryption.
        long rdlen = ;              //This is the total number of bytes written.
        long totlen = fin.Length;    //This is the total length of the input file.
        int len;                     //This is the number of bytes to be written at a time. 

        DES des = new DESCryptoServiceProvider();
        CryptoStream encStream = new CryptoStream(fout, des.CreateEncryptor(desKey, desIV), CryptoStreamMode.Write); 

        //Read from the input file, then encrypt and write to the output file.
        while (rdlen < totlen)
        {
            len = fin.Read(bin, , );
            encStream.Write(bin, , len);
            rdlen = rdlen + len;
        } 

        encStream.Close();
        fout.Close();
        fin.Close();
    } 

    //解密文件
    private static void DecryptData(String inName, String outName, byte[] desKey, byte[] desIV)
    {
        //Create the file streams to handle the input and output files.
        FileStream fin = new FileStream(inName, FileMode.Open, FileAccess.Read);
        FileStream fout = new FileStream(outName, FileMode.OpenOrCreate, FileAccess.Write);
        fout.SetLength(); 

        //Create variables to help with read and write.
        byte[] bin = new byte[]; //This is intermediate storage for the encryption.
        long rdlen = ;              //This is the total number of bytes written.
        long totlen = fin.Length;    //This is the total length of the input file.
        int len;                     //This is the number of bytes to be written at a time. 

        DES des = new DESCryptoServiceProvider();
        CryptoStream encStream = new CryptoStream(fout, des.CreateDecryptor(desKey, desIV), CryptoStreamMode.Write); 

        //Read from the input file, then encrypt and write to the output file.
        while (rdlen < totlen)
        {
            len = fin.Read(bin, , );
            encStream.Write(bin, , len);
            rdlen = rdlen + len;
        } 

        encStream.Close();
        fout.Close();
        fin.Close(); 

}
using System;
using System.Security.Cryptography;//这个是处理文字编码的前提
using System.Text;
using System.IO;
/// <summary>
/// DES加密方法
/// </summary>
/// <param name="strPlain">明文</param>
/// <param name="strDESKey">密钥</param>
/// <param name="strDESIV">向量</param>
/// <returns>密文</returns>
public string DESEncrypt(string strPlain,string strDESKey,string strDESIV)
{
 //把密钥转换成字节数组
 byte[] bytesDESKey=ASCIIEncoding.ASCII.GetBytes(strDESKey);
 //把向量转换成字节数组
 byte[] bytesDESIV=ASCIIEncoding.ASCII.GetBytes(strDESIV);
 //声明1个新的DES对象
 DESCryptoServiceProvider desEncrypt=new DESCryptoServiceProvider();
 //开辟一块内存流
 MemoryStream msEncrypt=new MemoryStream();
 //把内存流对象包装成加密流对象
 CryptoStream csEncrypt=new CryptoStream(msEncrypt,desEncrypt.CreateEncryptor(bytesDESKey,bytesDESIV),CryptoStreamMode.Write);
 //把加密流对象包装成写入流对象
 StreamWriter swEncrypt=new StreamWriter(csEncrypt);
 //写入流对象写入明文
 swEncrypt.WriteLine(strPlain);
 //写入流关闭
 swEncrypt.Close();
 //加密流关闭
 csEncrypt.Close();
 //把内存流转换成字节数组，内存流现在已经是密文了
 byte[] bytesCipher=msEncrypt.ToArray();
 //内存流关闭
 msEncrypt.Close();
 //把密文字节数组转换为字符串，并返回
 return UnicodeEncoding.Unicode.GetString(bytesCipher);
}

/// <summary>
/// DES解密方法
/// </summary>
/// <param name="strCipher">密文</param>
/// <param name="strDESKey">密钥</param>
/// <param name="strDESIV">向量</param>
/// <returns>明文</returns>
public string DESDecrypt(string strCipher,string strDESKey,string strDESIV)
{
 //把密钥转换成字节数组
 byte[] bytesDESKey=ASCIIEncoding.ASCII.GetBytes(strDESKey);
 //把向量转换成字节数组
 byte[] bytesDESIV=ASCIIEncoding.ASCII.GetBytes(strDESIV);
 //把密文转换成字节数组
 byte[] bytesCipher=UnicodeEncoding.Unicode.GetBytes(strCipher);
 //声明1个新的DES对象
 DESCryptoServiceProvider desDecrypt=new DESCryptoServiceProvider();
 //开辟一块内存流，并存放密文字节数组
 MemoryStream msDecrypt=new MemoryStream(bytesCipher);
 //把内存流对象包装成解密流对象
 CryptoStream csDecrypt=new CryptoStream(msDecrypt,desDecrypt.CreateDecryptor(bytesDESKey,bytesDESIV),CryptoStreamMode.Read);
 //把解密流对象包装成读出流对象
 StreamReader srDecrypt=new StreamReader(csDecrypt);
 //明文=读出流的读出内容
 string strPlainText=srDecrypt.ReadLine();
 //读出流关闭
 srDecrypt.Close();
 //解密流关闭
 csDecrypt.Close();
 //内存流关闭
 msDecrypt.Close();
 //返回明文
 return strPlainText;
}
简单加密基础

 　　　　static void Main(string[] args)
        {
            Console.WriteLine("请输入四位整数：");
            int i = int.Parse(Console.ReadLine());

            int first = i / ;
            int second = (i / ) % ;
            int third = (i / ) % ;
            int forth = i % ;

            Console.WriteLine(first + " " + second + " " + third + " " + forth);

            first = (first + ) % ;
            second = (second + ) % ;
            third = (third + ) % ;
            forth = (forth + ) % ;

            int temp = third;
            third = first;
            first = temp;

            temp = forth;
            forth = second;
            second = temp;

            int pass = first *  + second *  + third *  + forth;

            Console.WriteLine("Now is " + pass);
            Console.ReadLine();
        }

 private void btn_Encrypt_Click(object sender, EventArgs e)
         {
             int P_NumIn,P_CommonNum;
             //判断是否是数字
             if (int.TryParse(txtNumIn.Text, out P_NumIn) && int.TryParse(txtCommonNum.Text, out P_CommonNum))
             {
                 txtResult.Text = (P_NumIn ^ P_CommonNum).ToString();
                 txtReceive.Text = txtResult.Text;
             }
             else
             {
                 MessageBox.Show("请输入数字","一点小插曲",MessageBoxButtons.RetryCancel,MessageBoxIcon.Error);
             }
         }

         private void btn_Revert_Click(object sender, EventArgs e)
         {
             int P_YouKnow;
             if(int.TryParse(txtYouKnow.Text,out P_YouKnow))
             {
                 txtAnswer.Text = (P_YouKnow ^ (int.Parse(txtReceive.Text))).ToString();
             }
             else
             {
                 MessageBox.Show("请输入数字", "一点小插曲", MessageBoxButtons.RetryCancel, MessageBoxIcon.Error);
             }
         }