C# DES 加密/解密類庫，支援檔案和中文/UNICODE字元，返回BASE64編碼字串

using System;using System.Collections.Generic;using System.Text;using System.IO;using System.Security;using System.Security.Cryptography;/*---------------------------------------------- *  DES加密、解密類庫，字串加密結果使用BASE64編碼返回，支援檔案的加密和解密 *  作者： 三角貓/DeltaCat *  網址： http://www.zu14.cn *  轉載務必保留此資訊 * --------------------------------------------- */namespace ZU14{    public sealed class DES    {        string iv = "1234的yzo";        string key = "123在yzo";        /// <summary>        /// DES加密位移量，必須是>=8位長的字串        /// </summary>        public string IV        {            get { return iv; }            set { iv = value; }        }        /// <summary>        /// DES加密的私密金鑰，必須是8位長的字串        /// </summary>        public string Key        {            get { return key; }            set { key = value; }        }        /// <summary>        /// 對字串進行DES加密        /// </summary>        /// <param name="sourceString">待加密的字串</param>        /// <returns>加密後的BASE64編碼的字串</returns>        public string Encrypt(string sourceString)        {            byte[] btKey = Encoding.Default.GetBytes(key);            byte[] btIV = Encoding.Default.GetBytes(iv);            DESCryptoServiceProvider des = new DESCryptoServiceProvider();            using (MemoryStream ms = new MemoryStream())            {                byte[] inData = Encoding.Default.GetBytes(sourceString);                try                {                    using (CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(btKey, btIV), CryptoStreamMode.Write))                    {                        cs.Write(inData, 0, inData.Length);                        cs.FlushFinalBlock();                    }                    return Convert.ToBase64String(ms.ToArray());                }                catch                {                    throw;                }            }        }        /// <summary>        /// 對DES加密後的字串進行解密        /// </summary>        /// <param name="encryptedString">待解密的字串</param>        /// <returns>解密後的字串</returns>        public string Decrypt(string encryptedString)        {            byte[] btKey = Encoding.Default.GetBytes(key);            byte[] btIV = Encoding.Default.GetBytes(iv);            DESCryptoServiceProvider des = new DESCryptoServiceProvider();            using (MemoryStream ms = new MemoryStream())            {                byte[] inData = Convert.FromBase64String(encryptedString);                try                {                    using (CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(btKey, btIV), CryptoStreamMode.Write))                    {                        cs.Write(inData, 0, inData.Length);                        cs.FlushFinalBlock();                    }                    return Encoding.Default.GetString(ms.ToArray());                }                catch                {                    throw;                }            }        }        /// <summary>        /// 對檔案內容進行DES加密        /// </summary>        /// <param name="sourceFile">待加密的檔案絕對路徑</param>        /// <param name="destFile">加密後的檔案儲存的絕對路徑</param>        public void EncryptFile(string sourceFile, string destFile)        {            if (!File.Exists(sourceFile)) throw new FileNotFoundException("指定的檔案路徑不存在！", sourceFile);            byte[] btKey = Encoding.Default.GetBytes(key);            byte[] btIV = Encoding.Default.GetBytes(iv);            DESCryptoServiceProvider des = new DESCryptoServiceProvider();            byte[] btFile = File.ReadAllBytes(sourceFile);            using (FileStream fs = new FileStream(destFile, FileMode.Create, FileAccess.Write))            {                try                {                    using (CryptoStream cs = new CryptoStream(fs, des.CreateEncryptor(btKey, btIV), CryptoStreamMode.Write))                    {                        cs.Write(btFile, 0, btFile.Length);                        cs.FlushFinalBlock();                    }                }                catch                {                    throw;                }                finally                {                    fs.Close();                }            }        }        /// <summary>        /// 對檔案內容進行DES加密，加密後覆蓋掉原來的檔案        /// </summary>        /// <param name="sourceFile">待加密的檔案的絕對路徑</param>        public void EncryptFile(string sourceFile)        {            EncryptFile(sourceFile, sourceFile);        }        /// <summary>        /// 對檔案內容進行DES解密        /// </summary>        /// <param name="sourceFile">待解密的檔案絕對路徑</param>        /// <param name="destFile">解密後的檔案儲存的絕對路徑</param>        public void DecryptFile(string sourceFile, string destFile)        {            if (!File.Exists(sourceFile)) throw new FileNotFoundException("指定的檔案路徑不存在！", sourceFile);            byte[] btKey = Encoding.Default.GetBytes(key);            byte[] btIV = Encoding.Default.GetBytes(iv);            DESCryptoServiceProvider des = new DESCryptoServiceProvider();            byte[] btFile = File.ReadAllBytes(sourceFile);            using (FileStream fs = new FileStream(destFile, FileMode.Create, FileAccess.Write))            {                try                {                    using (CryptoStream cs = new CryptoStream(fs, des.CreateDecryptor(btKey, btIV), CryptoStreamMode.Write))                    {                        cs.Write(btFile, 0, btFile.Length);                        cs.FlushFinalBlock();                    }                }                catch                {                    throw;                }                finally                {                    fs.Close();                }            }        }        /// <summary>        /// 對檔案內容進行DES解密，加密後覆蓋掉原來的檔案        /// </summary>        /// <param name="sourceFile">待解密的檔案的絕對路徑</param>        public void DecryptFile(string sourceFile)        {            DecryptFile(sourceFile, sourceFile);        }    }}

使用的例子：
ZU14.DES des = new ZU14.DES();des.IV = "abcd哈哈笑";des.Key = "必須八位";string es = des.Encrypt("在");Console.WriteLine(es);Console.Write(des.Decrypt(es));des.EncryptFile(@"d:\a.txt", @"d:\b.txt");des.DecryptFile(@"d:\b.txt");Console.ReadKey(true); 
OK了。