A method of symmetric encryption and decryption C # tool class

Using system;using system.collections.generic;using system.text;using system.io;using System.Security.Cryptography; Namespace CMD. edi{public class Encrypthandler {//<summary>///encryption string///</summary> PU            Blic static string Encrypt (string password, string cleartext) {string password2 = "Ahbool";            string cipher;            char[] key = new CHAR[8]; if (password. Length > 8) {password = password.            Remove (8); } password. CopyTo (0, key, 0, password.            Length);            Char[] IV = new CHAR[8]; if (Password2. Length > 8) {password2 = Password2.            Remove (8); } password2. CopyTo (0, IV, 0, Password2.            Length); if (cleartext = = null) {return string.            Empty;            } symmetricalgorithm serviceprovider = new DESCryptoServiceProvider (); ServiceprovideR.key = Encoding.ASCII.GetBytes (Key);            SERVICEPROVIDER.IV = Encoding.ASCII.GetBytes (IV);            MemoryStream MemoryStream = new MemoryStream (); CryptoStream cryptostream = new CryptoStream (MemoryStream, Serviceprovider.createencryptor (), CryptoStreamMode.Write            );            StreamWriter StreamWriter = new StreamWriter (CryptoStream);            StreamWriter.Write (cleartext);            Streamwriter.dispose ();            Cryptostream.dispose ();            byte[] SignData = Memorystream.toarray ();            Memorystream.dispose ();            Serviceprovider.clear ();            cipher = convert.tobase64string (signdata);        return cipher; }//<summary>//Decrypt string///</summary> public static string Decrypt (String PASSW            Ord, String ciphertext) {string password2 = "Ahbool"; string cipher = string.            Empty;              try {char[] key = new CHAR[8];  if (password. Length > 8) {password = password.                Remove (8); } password. CopyTo (0, key, 0, password.                Length);                Char[] IV = new CHAR[8]; if (Password2. Length > 8) {password2 = Password2.                Remove (8); } password2. CopyTo (0, IV, 0, Password2.                Length);                if (ciphertext = = null) {return cipher;                } symmetricalgorithm serviceprovider = new DESCryptoServiceProvider ();                Serviceprovider.key = Encoding.ASCII.GetBytes (Key);                SERVICEPROVIDER.IV = Encoding.ASCII.GetBytes (IV);                byte[] Contentarray = convert.frombase64string (ciphertext);                MemoryStream MemoryStream = new MemoryStream (Contentarray); CryptoStream cryptostream = new CryptoStream (MemoryStream, Serviceprovider.createdecryptor (), CryptoStreamMOde.                Read);                StreamReader StreamReader = new StreamReader (CryptoStream);                cipher = Streamreader.readtoend ();                Streamreader.dispose ();                Cryptostream.dispose ();                Memorystream.dispose ();            Serviceprovider.clear ();            } catch (Exception ex) {throw new SystemException ("Key error, packet decryption failed.");        } return cipher; }    }}

　　

A method of symmetric encryption and decryption C # tool class