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public sealed class EncryptUtils    {        #region Base64加密解密        /// 
        /// Base64加密        /// 
        /// 需要加密的字符串        /// 
             public static string Base64Encrypt(string input)        {            return Base64Encrypt(input, new UTF8Encoding());        }        /// 
        /// Base64加密        /// 
        /// 需要加密的字符串        /// 字符编码        /// 
             public static string Base64Encrypt(string input, Encoding encode)        {            return Convert.ToBase64String(encode.GetBytes(input));        }        /// 
        /// Base64解密        /// 
        /// 需要解密的字符串        /// 
             public static string Base64Decrypt(string input)        {            return Base64Decrypt(input, new UTF8Encoding());        }        /// 
        /// Base64解密        /// 
        /// 需要解密的字符串        /// 字符的编码        /// 
             public static string Base64Decrypt(string input, Encoding encode)        {            return encode.GetString(Convert.FromBase64String(input));        }        #endregion        #region DES加密解密        /// 
        /// DES加密        /// 
        /// 加密数据        /// 8位字符的密钥字符串        /// 8位字符的初始化向量字符串        /// 
             public static string DESEncrypt(string data, string key, string iv)        {            byte[] byKey = System.Text.ASCIIEncoding.ASCII.GetBytes(key);            byte[] byIV = System.Text.ASCIIEncoding.ASCII.GetBytes(iv);            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);        }        /// 
        /// DES解密        /// 
        /// 解密数据        /// 8位字符的密钥字符串(需要和加密时相同)        /// 8位字符的初始化向量字符串(需要和加密时相同)        /// 
             public static string DESDecrypt(string data, string key, string iv)        {            byte[] byKey = System.Text.ASCIIEncoding.ASCII.GetBytes(key);            byte[] byIV = System.Text.ASCIIEncoding.ASCII.GetBytes(iv);            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();        }        #endregion        #region MD5加密        /// 
        /// MD5加密        /// 
        /// 需要加密的字符串        /// 
             public static string MD5Encrypt(string input)        {            return MD5Encrypt(input, new UTF8Encoding());        }        /// 
        /// MD5加密        /// 
        /// 需要加密的字符串        /// 字符的编码        /// 
             public static string MD5Encrypt(string input, Encoding encode)        {            MD5 md5 = new MD5CryptoServiceProvider();            byte[] t = md5.ComputeHash(encode.GetBytes(input));            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();        }        /// 
        /// MD5对文件流加密        /// 
        ///         /// 
             public static string MD5Encrypt(Stream stream)        {            MD5 md5serv = MD5CryptoServiceProvider.Create();            byte[] buffer = md5serv.ComputeHash(stream);            StringBuilder sb = new StringBuilder();            foreach (byte var in buffer)                sb.Append(var.ToString("x2"));            return sb.ToString();        }        /// 
        /// MD5加密(返回16位加密串)        /// 
        ///         ///         /// 
             public static string MD5Encrypt16(string input, Encoding encode)        {            MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();            string result = BitConverter.ToString(md5.ComputeHash(encode.GetBytes(input)), 4, 8);            result = result.Replace("-", "");            return result;        }        #endregion        #region 3DES 加密解密        public static string DES3Encrypt(string data, string key)        {            TripleDESCryptoServiceProvider DES = new TripleDESCryptoServiceProvider();            DES.Key = ASCIIEncoding.ASCII.GetBytes(key);            DES.Mode = CipherMode.CBC;            DES.Padding = PaddingMode.PKCS7;            ICryptoTransform DESEncrypt = DES.CreateEncryptor();            byte[] Buffer = ASCIIEncoding.ASCII.GetBytes(data);            return Convert.ToBase64String(DESEncrypt.TransformFinalBlock(Buffer, 0, Buffer.Length));        }        public static string DES3Decrypt(string data, string key)        {            TripleDESCryptoServiceProvider DES = new TripleDESCryptoServiceProvider();            DES.Key = ASCIIEncoding.ASCII.GetBytes(key);            DES.Mode = CipherMode.CBC;            DES.Padding = System.Security.Cryptography.PaddingMode.PKCS7;            ICryptoTransform DESDecrypt = DES.CreateDecryptor();            string result = "";            try            {                byte[] Buffer = Convert.FromBase64String(data);                result = ASCIIEncoding.ASCII.GetString(DESDecrypt.TransformFinalBlock(Buffer, 0, Buffer.Length));            }            catch (Exception e)            {            }            return result;        }        #endregion    }