1、方法一 (不可逆加密) 

   public string EncryptPassword(string PasswordString,string PasswordFormat ) 

   { 

     string   encryptPassword = null;

     if (PasswordFormat="SHA1"){ 

           encryptPassword=FormsAuthortication.HashPasswordForStoringInConfigFile(PasswordString ,"SHA1"); 

         } 

         elseif (PasswordFormat="MD5") 

     {

      encryptPassword=FormsAuthortication.HashPasswordForStoringInConfigFile(PasswordString ,"MD5"); 

         }

    return encryptPassword ;

}


2、方法二 (可逆加密)


    public interface IBindesh

{

    string encode(string str);

    string decode(string str);

}


public class EncryptionDecryption : IBindesh

    {

        public string encode(string str)

        {

            string htext = ""; 


            for ( int i = 0; i < str.Length; i++)

            {

                      htext = htext + (char) (str[i] + 10 - 1 * 2);

                  }

            return htext;

              }


        public string decode(string str)

        {

            string dtext = ""; 


            for ( int i=0; i < str.Length; i++)

            {

                      dtext = dtext + (char) (str[i] - 10 + 1*2);

                  }

            return dtext;

              }


3、方法三 (可逆加密)



        const string KEY_64 = "VavicApp";//注意了,是8个字符,64位


        const string IV_64 = "VavicApp"; 

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(), 0, (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();

              }


4,md5(32位加密)

public string GetMD5(string s, string _input_charset)

    {


        /// <summary>

        /// 与ASP兼容的MD5加密算法

        /// </summary>


             MD5 md5 = new MD5CryptoServiceProvider();

        byte[] t = md5.ComputeHash(Encoding.GetEncoding(_input_charset).GetBytes(s));

             StringBuilder sb = new StringBuilder(32);

        for (int i = 0; i < t.Length; i++)

        {

                 sb.Append(t[i].ToString("x").PadLeft(2, '0'));

             }

        return sb.ToString();

         }

(16位加密)


public static string GetMd5Str(string ConvertString)

    {

             MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();

        string t2 =BitConverter.ToString(md5.ComputeHash(UTF8Encoding.Default.GetBytes(ConvertString)), 4, 8);

             t2 = t2.Replace("-", "");

        return t2;

         }


5、加解文本文件​​


    //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(0);


        //Create variables to help with read and write.

        byte[] bin = new byte[100]; //This is intermediate storage for the encryption.

        long rdlen = 0;              //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, 0, 100);

                 encStream.Write(bin, 0, 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(0);


        //Create variables to help with read and write.

        byte[] bin = new byte[100]; //This is intermediate storage for the encryption.

        long rdlen = 0;              //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, 0, 100);

                 encStream.Write(bin, 0, len);

                 rdlen = rdlen + len;

             }


             encStream.Close();

             fout.Close();

             fin.Close();

         }