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DES Class

Represents the base class for the Data Encryption Standard (DES) algorithm from which all DES implementations must derive.

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

[ComVisibleAttribute(true)] 
public abstract class DES : SymmetricAlgorithm
/** @attribute ComVisibleAttribute(true) */ 
public abstract class DES extends SymmetricAlgorithm
ComVisibleAttribute(true) 
public abstract class DES extends SymmetricAlgorithm

This algorithm supports a key length of 64 bits.

The following code example method uses DESCryptoServiceProvider (an implementation of DES) with the specified key (Key) and initialization vector (IV) to encrypt a file specified by inName. It then outputs the encrypted result to the file specified by outName.

private static void EncryptData(String inName, String outName, byte[] desKey, byte[] desIV)
 {    
     //Create the file streams to handle the input and output files.
     FileStream fin = new FileStream(inName, FileMode.Open, FileAccess.Read);
     FileStream fout = new FileStream(outName, FileMode.OpenOrCreate, FileAccess.Write);
     fout.SetLength(0);
       
     //Create variables to help with read and write.
     byte[] bin = new byte[100]; //This is intermediate storage for the encryption.
     long rdlen = 0;              //This is the total number of bytes written.
     long totlen = fin.Length;    //This is the total length of the input file.
     int len;                     //This is the number of bytes to be written at a time.
 
     DES des = new DESCryptoServiceProvider();          
     CryptoStream encStream = new CryptoStream(fout, des.CreateEncryptor(desKey, desIV), CryptoStreamMode.Write);
                
     Console.WriteLine("Encrypting...");
 
     //Read from the input file, then encrypt and write to the output file.
     while(rdlen < totlen)
     {
         len = fin.Read(bin, 0, 100);
         encStream.Write(bin, 0, len);
         rdlen = rdlen + len;
         Console.WriteLine("{0} bytes processed", rdlen);
     }
 
     encStream.Close();  
     fout.Close();
     fin.Close();                   
 }

private static void EncryptData(String inName, 
    String outName, ubyte desKey[], ubyte desIV[])
{
    //Create the file streams to handle the input and output files.
    FileStream fin = new FileStream(inName, FileMode.Open, 
        FileAccess.Read);
    FileStream fout = new FileStream(outName, FileMode.OpenOrCreate, 
        FileAccess.Write);

    fout.SetLength(0);

    // Create variables to help with read and write.        
    ubyte bin[] = new ubyte[100];  // This is intermediate 
                                   // storage for the encryption.
    long rdlen = 0; // This is the total 
                    // number of bytes written.
    long totlen = fin.get_Length(); // This is the total 
                                    // length of the input file.        
    int len; //This is the number of bytes to be written at a time.

    DES des = new DESCryptoServiceProvider();
    CryptoStream encStream = new CryptoStream(fout, 
        des.CreateEncryptor(desKey, desIV), CryptoStreamMode.Write);

    Console.WriteLine("Encrypting...");

    //Read from the input file, then encrypt and write to the output file.
    while (rdlen < totlen) {
        len = fin.Read(bin, 0, 100);
        encStream.Write(bin, 0, len);
        rdlen = rdlen + len;
        Console.WriteLine("{0} bytes processed", 
            System.Convert.ToString(rdlen));
    }

    encStream.Close();
    fout.Close();
    fin.Close();
} //EncryptData

Decryption can be handled in the same way; use CreateDecryptor instead of CreateEncryptor. The same key (Key) and initialization vector (IV) used to encrypt the file must be used to decrypt it.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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

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

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0
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