整理封装的加密解密类,使用DES

using System;

using System.Security;
using System.Security.Cryptography;
using System.IO;
namespace TexSelect
{
    /**//// <summary>
    /// 加密解密类
    /// </summary>
    public class DESCoding
    {
        public DESCoding()
        {
            //
            // TODO: 在此处添加构造函数逻辑
            //
        }
        /**//// <summary>
        /// 密钥,已经赋默认值,可改
        /// </summary>
        private string key_64="VavicApp";
        /**//// <summary>
        /// 密钥,已经赋默认值,可改
        /// </summary>
        private string iv_64="VavicApp";

        /**//// <summary>
        /// 密钥
        /// </summary>
        public string KEY_64
        {
            get{return key_64;}
            set{key_64=value;}
        }
        /**//// <summary>
        /// 密钥
        /// </summary>
        public string IV_64
        {
            get{return iv_64;}
            set{iv_64=value;}
        }

        /**//// <summary>
        /// 加密方法
        /// </summary>
        /// <param name="data">要加密的字符串</param>
        /// <param name="KEY_64">密钥</param>
        /// <param name="IV_64">密钥</param>
        /// <returns>加密后的字符串</returns>
        public string Encode(string data,string KEY_64,string IV_64)
        {
            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);
        }
        /**//// <summary>
        /// 加密方法
        /// </summary>
        /// <param name="data">要加密的字符串</param>
        /// <returns>加密后的字符串</returns>
        public string Encode(string data)
        {
            byte[] byKey = System.Text.ASCIIEncoding.ASCII.GetBytes(this.KEY_64);
            byte[] byIV = System.Text.ASCIIEncoding.ASCII.GetBytes(this.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);
        }

        /**//// <summary>
        /// 解密方法
        /// </summary>
        /// <param name="data">要解密的字符串</param>
        /// <param name="KEY_64">密钥</param>
        /// <param name="IV_64">密钥</param>
        /// <returns>解密后的字符串</returns>
        public string Decode(string data,string KEY_64,string IV_64)
                             
        {   
            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();
        }
        /**//// <summary>
        /// 解密方法
        /// </summary>
        /// <param name="data">要解密的字符串</param>
        /// <returns>解密后的字符串</returns>
        public string Decode(string data)
                             
        {   
            byte[] byKey = System.Text.ASCIIEncoding.ASCII.GetBytes(this.KEY_64);
            byte[] byIV = System.Text.ASCIIEncoding.ASCII.GetBytes(this.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();
        }
    }


}

添加了两个密钥属性,可以自定义赋值,也可以使用自带的默认密钥,使用默认的密钥可以使用简单的加密解密方法,省事.