C # implement 3DES encryption for 24-bit keys

Using System;
Using System. Collections. Generic;
Using System. text;
Using System. IO;
Using System. Security. cryptography;

Namespace Leleapplication1
{
Class Program
{
Public   Static   String Encrypt3des ( String A_strstring, String A_strkey)
{
Tripledescryptoserviceprovider des =   New Tripledescryptoserviceprovider ();

Des. Key=Asciiencoding. ASCII. getbytes (a_strkey );
Des. Mode=Ciphermode. ECB;

Icryptotransform desencrypt=Des. createencryptor ();

byte [] buffer = asciiencoding. ASCII. getbytes (a_strstring);
return convert. tobase64string (desencrypt. transformfinalblock (buffer, 0 , buffer. length);
}

Public static string decrypt3des ( string a_strstring, string a_strkey)
{< br> tripledescryptoserviceprovider des = New tripledescryptoserviceprovider ();

Des. Key=Asciiencoding. ASCII. getbytes (a_strkey );
Des. Mode=Ciphermode. ECB;
Des. padding=System. Security. cryptography. paddingmode. pkcs7;

Icryptotransform desdecrypt=Des. createdecryptor ();

String Result =   "" ;
Try
{
Byte [] Buffer = Convert. frombase64string (a_strstring );
Result = Asciiencoding. ASCII. getstring (desdecrypt. transformfinalblock (buffer, 0 , Buffer. Length ));
}
Catch (Exception E)
{

}< br> return result;
}

static void main ( string [] ARGs)
{< br> console. writeline (encrypt3des ( " 999999999 " , " # s ^ un2ye31 " );
console. readline ();
}< BR >}< br>