c#加密 可逆与不可逆MD5 加密

1、方法一 (不可逆加密) srxljl

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)srxljl

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)srxljl

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) srxljl

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)srxljl

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srxljl

//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();
         }