Security in cryptography
Cryptography play important role in Security. 
Using Cryptography we can Encrypt and Decrypt the information in the Coded form.
How we Encrypt the File using DES (Data 
Encryption standard) algorithm.
1.Open visual studio and create a project
2.Add the following assembly on the page
using 
Microsoft.VisualBasic;
using 
System;
using 
System.Collections;
using 
System.Collections.Generic;
using 
System.Data;
using 
System.Diagnostics;
using 
System.Security;
using 
System.Security.Cryptography;
using 
System.Text;
using 
System.IO;
3.Now write the Code in the 
Page
public
class Tester
{
   
public static
void Main()
    {
        
try
        {
           
DESCryptoServiceProvider myDESProvider =
new 
DESCryptoServiceProvider();
             
myDESProvider.Key = ASCIIEncoding.ASCII.GetBytes("12345678");
            
myDESProvider.IV = ASCIIEncoding.ASCII.GetBytes("12345678");
           
ICryptoTransform myICryptoTransform = 
myDESProvider.CreateEncryptor(myDESProvider.Key, myDESProvider.IV);
           
FileStream ProcessFileStream =
new FileStream("test.txt",
FileMode.Open, 
FileAccess.Read);
           
FileStream ResultFileStream =
new FileStream("testDes.txt",
FileMode.Create, 
FileAccess.Write);
           
CryptoStream myCryptoStream =
new CryptoStream(ResultFileStream, 
myICryptoTransform, CryptoStreamMode.Write);
            
byte[] bytearrayinput = 
new byte[ProcessFileStream.Length];
             
ProcessFileStream.Read(bytearrayinput, 0, bytearrayinput.Length);
            
myCryptoStream.Write(bytearrayinput, 0, bytearrayinput.Length);
             
myCryptoStream.Close();
            
ProcessFileStream.Close();
            
ResultFileStream.Close();
        }
       
catch (Exception 
ex)
        {
           
Console.WriteLine(ex.Message); 
        }
    }
}
4.Now 
create a text file in the folder D:\New Folder 
(2)\ConsoleApplication4\ConsoleApplication4\bin\Debug (My text file path) with 
some text which you want to encrypt .
Now start 
debugging, you will see a testDes.txt folder automatically generated in the 
folder that is encrypted folder.