3des,aes,md5加密解密方法

----------des 8位key---
        /// <summary>
        /// 字符串加密
        /// </summary>
        /// <param name="strText">要加密的字符串</param>
        /// <param name="strEncrKey">密钥</param>
        /// <returns>返回加密后的字符串</returns>
        public static string DesEncrypt(string strText, string strEncrKey)
        {
            byte[] byKey = null;
            byte[] IV = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };
            try
            {
                byKey = System.Text.Encoding.UTF8.GetBytes(strEncrKey.Substring(0, strEncrKey.Length));
                DESCryptoServiceProvider des = new DESCryptoServiceProvider();
                byte[] inputByteArray = Encoding.UTF8.GetBytes(strText);
                MemoryStream ms = new MemoryStream();
                CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(byKey, IV), CryptoStreamMode.Write);
                cs.Write(inputByteArray, 0, inputByteArray.Length);
                cs.FlushFinalBlock();
                return Convert.ToBase64String(ms.ToArray());
            }
            catch (System.Exception error)
            {
                return "error:" + error.Message + "/r";
            }
        }
        /// <summary>
        /// 字符串解密
        /// </summary>
        /// <param name="strText">要解密的字符串</param>
        /// <param name="sDecrKey">密钥</param>
        /// <returns>返回解密后的字符串</returns>
        public static string DesDecrypt(string strText, string sDecrKey)
        {
            byte[] byKey = null;
            byte[] IV = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };
            byte[] inputByteArray = new Byte[strText.Length];
            try
            {
                byKey = System.Text.Encoding.UTF8.GetBytes(sDecrKey.Substring(0, 8));
                DESCryptoServiceProvider des = new DESCryptoServiceProvider();
                inputByteArray = Convert.FromBase64String(strText);
                MemoryStream ms = new MemoryStream();
                CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(byKey, IV), CryptoStreamMode.Write);
                cs.Write(inputByteArray, 0, inputByteArray.Length);
                cs.FlushFinalBlock();
                System.Text.Encoding encoding = new System.Text.UTF8Encoding();
                return encoding.GetString(ms.ToArray());
            }
            catch (System.Exception error)
            {
                return "error:" + error.Message + "/r";
            }

        }
-------3des 16位key---------
///   <summary>
        ///   3des加密字符串
        ///   </summary>
        ///   <param   name= "a_strString "> 要加密的字符串 </param>
        ///   <param   name= "a_strKey "> 密钥 </param>
        ///   <returns> 加密后并经base64编码的字符串 </returns>
        ///   <remarks> 静态方法，采用默认ascii编码 </remarks>
        public static string EncryptDES16(string a_strString, string a_strKey)
        {
            DESCryptoServiceProvider DES = new DESCryptoServiceProvider();

            //TripleDESCryptoServiceProvider DES = new TripleDESCryptoServiceProvider();
            //MD5CryptoServiceProvider hashMD5 = new MD5CryptoServiceProvider();
            byte[] b = strToToHexByte(a_strKey);

            DES.Key = b;
            // DES.IV = b;
            //  DES.Key = b;//ASCIIEncoding.ASCII.GetBytes(a_strKey);//hashMD5.ComputeHash(ASCIIEncoding.ASCII.GetBytes(a_strKey));
            DES.Mode = CipherMode.ECB;
            DES.Padding = PaddingMode.PKCS7;

 

            ICryptoTransform DESEncrypt = DES.CreateEncryptor();

            byte[] Buffer = ASCIIEncoding.UTF8.GetBytes(a_strString);
            return Convert.ToBase64String(DESEncrypt.TransformFinalBlock(Buffer, 0, Buffer.Length));
        }//end   method

        private static byte[] strToToHexByte(string hexString)
        {
            byte[] returnBytes = new byte[hexString.Length / 2];
            for (int i = 0; i < returnBytes.Length; i++)
                returnBytes[i] = Convert.ToByte(hexString.Substring(i * 2, 2), 16);
            return returnBytes;
        }

        ///   <summary>
        ///   3des解密字符串
        ///   </summary>
        ///   <param   name= "a_strString "> 要解密的字符串 </param>
        ///   <param   name= "a_strKey "> 密钥 </param>
        ///   <returns> 解密后的字符串 </returns>
        ///   <exception   cref= " "> 密钥错误 </exception>
        ///   <remarks> 静态方法，采用默认ascii编码 </remarks>
        public static string DecryptDES16(string a_strString, string a_strKey)
        {
            DESCryptoServiceProvider DES = new DESCryptoServiceProvider();
            AesCryptoServiceProvider AES = new AesCryptoServiceProvider();

            DES.Key = strToToHexByte(a_strKey);
            DES.Mode = CipherMode.ECB;
            DES.Padding = PaddingMode.PKCS7;

            ICryptoTransform DESDecrypt = DES.CreateDecryptor();

            string result = " ";
            try
            {
                byte[] Buffer = Convert.FromBase64String(a_strString);
                result = ASCIIEncoding.UTF8.GetString(DESDecrypt.TransformFinalBlock(Buffer, 0, Buffer.Length));
            }
            catch (Exception e)
            {

                throw (new Exception("Invalid   Key   or   input   string   is   not   a   valid   base64   string ", e));
            }

            return result;
        }

----------AES----------
        public static byte[] AESEncript(byte[] s1, byte[] key, byte[] iv, byte[] mainkey)
        {

            AesCryptoServiceProvider acsp = new AesCryptoServiceProvider();
            acsp.Mode = CipherMode.ECB;
            acsp.Padding = PaddingMode.PKCS7 ;
            //acsp.Key = mainkey;
            MemoryStream mstream = new MemoryStream();

            CryptoStream cstream = new CryptoStream(mstream, acsp.CreateEncryptor(key, iv), CryptoStreamMode.Write);

            cstream.Write(s1, 0, s1.Length);

            cstream.FlushFinalBlock();

            byte[] outb1 = mstream.ToArray();

            cstream.Close();

            mstream.Close();

            return outb1;

        }

        private static byte[] _key1 = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF, 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };

        public static byte[] AESDecript(byte[] s2, byte[] key, byte[] iv, byte[] mainkey)
        {

            AesCryptoServiceProvider acsp = new AesCryptoServiceProvider();
            acsp.Mode = CipherMode.ECB;
            acsp.Padding = PaddingMode.PKCS7;
            //acsp.Key = mainkey;
            MemoryStream mtream2 = new MemoryStream();
            CryptoStream deStreame = new CryptoStream(mtream2, acsp.CreateDecryptor(key, iv), CryptoStreamMode.Write);

            deStreame.Write(s2, 0, s2.Length);

            deStreame.FlushFinalBlock();

            byte[] outs2 = mtream2.ToArray();

            mtream2.Close();

            deStreame.Close();

            return outs2;

        }

调用
AesCryptoServiceProvider acsp = new AesCryptoServiceProvider();
                byte[] skey = Encoding.Default.GetBytes(key);
                byte[] siv = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF, 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };
-------------md5--------------
public static string Md5(string str, int code)
        {
            if (code == 16) //16位MD5加密（取32位加密的9~25字符）
            {
                return System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(str, "MD5").ToLower().Substring(8, 16);
            }
            else//32位加密
            {
                return System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(str, "MD5").ToLower();
            }
        }
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