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DES.Create Method

Creates an instance of a cryptographic object to perform the Data Encryption Standard (DES) algorithm.

Namespace:  System.Security.Cryptography
Assembly:  mscorlib (in mscorlib.dll)

public static DES Create()

Return Value

Type: System.Security.Cryptography.DES
A cryptographic object.

Creates an instance of the DES object that can be used for encrypting and decrypting data.

The following code example shows how to create and use a DES object to encrypt and decrypt data in a file.

using System;
using System.Security.Cryptography;
using System.Text;
using System.IO;

class DESSample
{

    static void Main()
    {
        try
        {
            // Create a new DES object to generate a key 
            // and initialization vector (IV).
            DES DESalg = DES.Create();

            // Create a string to encrypt.
            string sData = "Here is some data to encrypt.";
            string FileName = "CText.txt";

            // Encrypt text to a file using the file name, key, and IV.
            EncryptTextToFile(sData, FileName, DESalg.Key, DESalg.IV);

            // Decrypt the text from a file using the file name, key, and IV.
            string Final = DecryptTextFromFile(FileName, DESalg.Key, DESalg.IV);

            // Display the decrypted string to the console.
            Console.WriteLine(Final);
        }
        catch (Exception e)
        {
            Console.WriteLine(e.Message);
        }

    }

    public static void EncryptTextToFile(String Data, String FileName, byte[] Key, byte[] IV)
    {
        try
        {
            // Create or open the specified file.
            FileStream fStream = File.Open(FileName,FileMode.OpenOrCreate);

            // Create a new DES object.
            DES DESalg = DES.Create();

            // Create a CryptoStream using the FileStream  
            // and the passed key and initialization vector (IV).
            CryptoStream cStream = new CryptoStream(fStream, 
                DESalg.CreateEncryptor(Key,IV), 
                CryptoStreamMode.Write); 

            // Create a StreamWriter using the CryptoStream.
            StreamWriter sWriter = new StreamWriter(cStream);

            // Write the data to the stream  
            // to encrypt it.
            sWriter.WriteLine(Data);

            // Close the streams and 
            // close the file.
            sWriter.Close();
            cStream.Close();
            fStream.Close();
        }
        catch(CryptographicException e)
        {
            Console.WriteLine("A Cryptographic error occurred: {0}", e.Message);
        }
        catch(UnauthorizedAccessException  e)
        {
            Console.WriteLine("A file error occurred: {0}", e.Message);
        }

    }

    public static string DecryptTextFromFile(String FileName, byte[] Key, byte[] IV)
    {
        try
        {
            // Create or open the specified file. 
            FileStream fStream = File.Open(FileName, FileMode.OpenOrCreate);

            // Create a new DES object.
            DES DESalg = DES.Create();

            // Create a CryptoStream using the FileStream  
            // and the passed key and initialization vector (IV).
            CryptoStream cStream = new CryptoStream(fStream, 
                DESalg.CreateDecryptor(Key,IV), 
                CryptoStreamMode.Read); 

            // Create a StreamReader using the CryptoStream.
            StreamReader sReader = new StreamReader(cStream);

            // Read the data from the stream  
            // to decrypt it.
            string val = sReader.ReadLine();

            // Close the streams and 
            // close the file.
            sReader.Close();
            cStream.Close();
            fStream.Close();

            // Return the string.  
            return val;
        }
        catch(CryptographicException e)
        {
            Console.WriteLine("A Cryptographic error occurred: {0}", e.Message);
            return null;
        }
        catch(UnauthorizedAccessException  e)
        {
            Console.WriteLine("A file error occurred: {0}", e.Message);
            return null;
        }
    }
}

The following code example shows how to create and use a DES object to encrypt and decrypt data in memory.

using System;
using System.Security.Cryptography;
using System.Text;
using System.IO;

class DESSample
{
    static void Main()
    {
        try
        {
            // Create a new DES object to generate a key 
            // and initialization vector (IV).
            DES DESalg = DES.Create();

            // Create a string to encrypt.
            string sData = "Here is some data to encrypt.";

            // Encrypt the string to an in-memory buffer.
            byte[] Data = EncryptTextToMemory(sData, DESalg.Key, DESalg.IV);

            // Decrypt the buffer back to a string.
            string Final = DecryptTextFromMemory(Data, DESalg.Key, DESalg.IV);

            // Display the decrypted string to the console.
            Console.WriteLine(Final);
        }
        catch (Exception e)
        {
            Console.WriteLine(e.Message);
        }

    }

    public static byte[] EncryptTextToMemory(string Data,  byte[] Key, byte[] IV)
    {
        try
        {
            // Create a MemoryStream.
            MemoryStream mStream = new MemoryStream();

            // Create a new DES object.
            DES DESalg = DES.Create();

            // Create a CryptoStream using the MemoryStream  
            // and the passed key and initialization vector (IV).
            CryptoStream cStream = new CryptoStream(mStream, 
                DESalg.CreateEncryptor(Key, IV), 
                CryptoStreamMode.Write);

            // Convert the passed string to a byte array.
            byte[] toEncrypt = new ASCIIEncoding().GetBytes(Data);

            // Write the byte array to the crypto stream and flush it.
            cStream.Write(toEncrypt, 0, toEncrypt.Length);
            cStream.FlushFinalBlock();

            // Get an array of bytes from the  
            // MemoryStream that holds the  
            // encrypted data.
            byte[] ret = mStream.ToArray();

            // Close the streams.
            cStream.Close();
            mStream.Close();

            // Return the encrypted buffer. 
            return ret;
        }
        catch(CryptographicException e)
        {
            Console.WriteLine("A Cryptographic error occurred: {0}", e.Message);
            return null;
        }

    }

    public static string DecryptTextFromMemory(byte[] Data,  byte[] Key, byte[] IV)
    {
        try
        {
            // Create a new MemoryStream using the passed  
            // array of encrypted data.
            MemoryStream msDecrypt = new MemoryStream(Data);

            // Create a new DES object.
            DES DESalg = DES.Create();

            // Create a CryptoStream using the MemoryStream  
            // and the passed key and initialization vector (IV).
            CryptoStream csDecrypt = new CryptoStream(msDecrypt, 
                DESalg.CreateDecryptor(Key, IV), 
                CryptoStreamMode.Read);

            // Create buffer to hold the decrypted data.
            byte[] fromEncrypt = new byte[Data.Length];

            // Read the decrypted data out of the crypto stream 
            // and place it into the temporary buffer.
            csDecrypt.Read(fromEncrypt, 0, fromEncrypt.Length);

            //Convert the buffer into a string and return it. 
            return new ASCIIEncoding().GetString(fromEncrypt);
        }
        catch(CryptographicException e)
        {
            Console.WriteLine("A Cryptographic error occurred: {0}", e.Message);
            return null;
        }
    }
}

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0

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