DES Class
Updated: February 2009
Represents the base class for the Data Encryption Standard (DES) algorithm from which all DES implementations must derive.
Assembly: mscorlib (in mscorlib.dll)
This algorithm supports a key length of 64 bits.
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A newer symmetric encryption algorithm, Advanced Encryption Standard (AES), is available. Consider using the Aes class instead of the DES class. |
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 Shared Sub EncryptData(inName As String, outName As String, _ desKey() As Byte, desIV() As Byte) 'Create the file streams to handle the input and output files. Dim fin As New FileStream(inName, FileMode.Open, FileAccess.Read) Dim fout As New FileStream(outName, FileMode.OpenOrCreate, _ FileAccess.Write) fout.SetLength(0) 'Create variables to help with read and write. Dim bin(4096) As Byte 'This is intermediate storage for the encryption. Dim rdlen As Long = 0 'This is the total number of bytes written. Dim totlen As Long = fin.Length 'Total length of the input file. Dim len As Integer 'This is the number of bytes to be written at a time. Dim des As New DESCryptoServiceProvider() Dim encStream As 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, 4096) encStream.Write(bin, 0, len) rdlen = Convert.ToInt32(rdlen + len / des.BlockSize * des.BlockSize) Console.WriteLine("Processed {0} bytes, {1} bytes total", len, _ rdlen) End While encStream.Close() End Sub
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.
System.Security.Cryptography.SymmetricAlgorithm
System.Security.Cryptography.DES
System.Security.Cryptography.DESCryptoServiceProvider
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.
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