C#加密解密方法小结

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不可逆加密

    (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();
    }
 

6、

using System;
using System.Collections.Generic;
using System.Text;
using System.Security.Cryptography;
using System.IO;

namespace Component
{
    public class Security
    {
        public Security()
        { 
        
        }

        //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(0, 8));
                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, 0, 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, 0, inputByteArray.Length);
                cStream.FlushFinalBlock();
                return Encoding.UTF8.GetString(mStream.ToArray());
            }
            catch
            {
                return decryptString;
            }
        } 


    }
}

文章出处：http://www.cnblogs.com/yiki/archive/2007/08/28/872373.html