using System;

using System.IO;

using System.Security.Cryptography;

using System.Text;

namespace GT.Common.DES

{

    /// <summary>

    /// 3DES加解密类

    /// </summary>

    public class DESHelper

    {

        //构造一个对称算法

        private SymmetricAlgorithm mCSP = new TripleDESCryptoServiceProvider();

        #region 加密解密函数

        /// <summary>

        /// 字符串的加密

        /// </summary>

        /// <param name="Value">要加密的字符串</param>

        /// <param name="sKey">密钥，必须32位</param>

        /// <param name="sIV">向量，必须是8个字符</param>

        /// <returns>加密后的字符串</returns>

        public string EncryptString(string Value, string sKey,string sIV)

        {

            try

            {

                if (string.IsNullOrWhiteSpace(sKey))

                {

                    sKey = key;

                }

                if (string.IsNullOrWhiteSpace(sIV))

                {

                    sIV = iv;

                }

                ICryptoTransform ct;

                MemoryStream ms;

                CryptoStream cs;

                byte[] byt;

                mCSP.Key = Convert.FromBase64String(sKey);

                byte[] biv=Encoding.Default.GetBytes (sIV);

                mCSP.IV = biv;

                //指定加密的运算模式

                mCSP.Mode = System.Security.Cryptography.CipherMode.ECB;

                //获取或设置加密算法的填充模式

                mCSP.Padding = System.Security.Cryptography.PaddingMode.PKCS7;

                ct = mCSP.CreateEncryptor(mCSP.Key, mCSP.IV);//创建加密对象

                byt = Encoding.UTF8.GetBytes(Value);

                ms = new MemoryStream();

                cs = new CryptoStream(ms, ct, CryptoStreamMode.Write);

                cs.Write(byt, , byt.Length);

                cs.FlushFinalBlock();

                cs.Close();

                return Convert.ToBase64String(ms.ToArray());

            }

            catch (Exception ex)

            {

                return ("Error in Encrypting " + ex.Message);

            }

        }

        /// <summary>

        /// 解密字符串

        /// </summary>

        /// <param name="Value">加密后的字符串</param>

        /// <param name="sKey">密钥，必须32位</param>

        /// <param name="sIV">向量，必须是12个字符</param>

        /// <returns>解密后的字符串</returns>

        public string DecryptString(string Value, string sKey, string sIV)

        {

            try

            {

                if (string.IsNullOrWhiteSpace(sKey))

                {

                    sKey = key;

                }

                if (string.IsNullOrWhiteSpace(sIV))

                {

                    sIV = iv;

                }

                ICryptoTransform ct;//加密转换运算

                MemoryStream ms;//内存流

                CryptoStream cs;//数据流连接到数据加密转换的流

                byte[] byt;

                //将3DES的密钥转换成byte

                mCSP.Key = Convert.FromBase64String(sKey);

                //将3DES的向量转换成byte

                mCSP.IV = Encoding.Default.GetBytes(sIV);

                mCSP.Mode = System.Security.Cryptography.CipherMode.ECB;

                mCSP.Padding = System.Security.Cryptography.PaddingMode.PKCS7;

                ct = mCSP.CreateDecryptor(mCSP.Key, mCSP.IV);//创建对称解密对象

                byt = Convert.FromBase64String(Value);

                ms = new MemoryStream();

                cs = new CryptoStream(ms, ct, CryptoStreamMode.Write);

                cs.Write(byt, , byt.Length);

                cs.FlushFinalBlock();

                cs.Close();

                return Encoding.UTF8.GetString(ms.ToArray());

            }

            catch (Exception ex)

            {

                return ("Error in Decrypting " + ex.Message);

            }

        }

        #endregion

        #region KEY

         //<!--不要轻易修改，一定要保证跟生产环境的一致，防止丢失-->

         //<!--秘钥32位-->

         public static readonly string key = "aybcwdefgh1ntv2x3qr4u5o6igklszmp";

         //<!--向量8位-->

         public static readonly string iv = "";

         #endregion

    }

}