3DES plus decryption, no limit on length

#region3DES/// <summary>        ///3DES Encryption/// </summary>        /// <param name= "strstring" >strings to be encrypted</param>        /// <param name= "Strkey" >secret key</param>        /// <returns></returns>         Public Static stringDes3encrypt (stringStrstring,stringstrkey) {strstring= strstring +"". PadLeft (8); byte[] bmsg = encoding.getencoding ("GBK").            GetBytes (strstring); intL = (Bmsg.length/ -+1) * -; byte[] btmsg =New byte[L];            Array.copy (Bmsg, btmsg, bmsg.length); byte[] Digestofpassword =Encoding.Default.GetBytes (strkey); byte[] Keybytes =New byte[ -];            Array.copy (Digestofpassword, Keybytes, digestofpassword.length);  for(intj =0, k = -; J <8; ) {Keybytes[k+ +] = keybytes[j++]; } TripleDESCryptoServiceProvider DES=NewTripleDESCryptoServiceProvider (); Des. Mode=CIPHERMODE.ECB; ICryptoTransform desencrypt=DES.            CreateEncryptor (Keybytes, keybytes); varDD = Desencrypt.transformfinalblock (btmsg,0, btmsg.length); returnByte2hex (DD). ToString (). Substring (0, (Bmsg.length/8+1) * -); }         Public StaticString Getadd (intlength, String strkey) {            byte[] btmsg =New byte[Length/2]; byte[] Digestofpassword =Encoding.UTF8.GetBytes (strkey); //byte[] Digestofpassword = Encoding.Default.GetBytes (strkey);            byte[] Keybytes =New byte[ -];            Array.copy (Digestofpassword, Keybytes, digestofpassword.length);  for(intj =0, k = -; J <8; ) {Keybytes[k+ +] = keybytes[j++]; } TripleDESCryptoServiceProvider DES=NewTripleDESCryptoServiceProvider (); Des. Mode=CIPHERMODE.ECB; ICryptoTransform desencrypt=DES.            CreateEncryptor (Keybytes, keybytes); varDD = Desencrypt.transformfinalblock (btmsg,0, btmsg.length); String RTN=Byte2hex (DD); returnRtn.        Substring (length); }        /// <summary>         ///byte array to 16 binary string/// </summary>         /// <param name= "bytes" ></param>         /// <returns></returns>         Private Static stringByte2hex (byte[] dd) {StringBuilder ret=NewStringBuilder (); foreach(varIteminchdd) {ret. AppendFormat ("{0:x2}", item); }            returnret.        ToString (); }        /// <summary>         ///string to 16 binary byte array/// </summary>         /// <param name= "hexstring" ></param>         /// <returns></returns>         Private Static byte[] Strtotohexbyte (stringhexstring) {hexstring= Hexstring.replace (" ",""); if((hexstring.length%2) !=0) hexstring+=" "; byte[] Returnbytes =New byte[Hexstring.length/2];  for(inti =0; i < returnbytes.length; i++) Returnbytes[i]= Convert.tobyte (hexstring.substring (i *2,2), -); returnreturnbytes; }        /// <summary>        ///3DES Decryption/// </summary>        /// <param name= "strstring" >the string to be decrypted</param>        /// <param name= "Strkey" >secret key</param>        /// <returns></returns>         Public Static stringDes3decrypt (stringStrstring,stringstrkey) {strstring+=Getadd (Strstring.length, strkey); byte[] Digestofpassword =Encoding.Default.GetBytes (strkey); byte[] Keybytes =New byte[ -];            Array.copy (Digestofpassword, Keybytes, digestofpassword.length);  for(intj =0, k = -; J <8; ) {Keybytes[k+ +] = keybytes[j++]; } TripleDESCryptoServiceProvider DES=NewTripleDESCryptoServiceProvider (); Des. Mode=CIPHERMODE.ECB; ICryptoTransform Desdecrypt=DES.            CreateDecryptor (Keybytes, keybytes); stringresult =""; Try            {                byte[] Buffer =Strtotohexbyte (strstring); byte[] bb = Desdecrypt.transformfinalblock (Buffer,0, buffer.length); Result= Encoding.GetEncoding ("GBK").            GetString (BB); }            Catch(Exception e) {Throwe; }            returnresult; }        #endregion

3DES plus decryption, no limit on length