DESCryptoServiceProvider Classe

Définition

public ref class DESCryptoServiceProvider sealed : System::Security::Cryptography::DES

public sealed class DESCryptoServiceProvider : System.Security.Cryptography.DES

[System.Runtime.InteropServices.ComVisible(true)]
public sealed class DESCryptoServiceProvider : System.Security.Cryptography.DES

type DESCryptoServiceProvider = class
    inherit DES

[<System.Runtime.InteropServices.ComVisible(true)>]
type DESCryptoServiceProvider = class
    inherit DES

Public NotInheritable Class DESCryptoServiceProvider
Inherits DES

Héritage

Object

SymmetricAlgorithm

DES

DESCryptoServiceProvider

Attributs

ComVisibleAttribute

Exemples

L’exemple de code suivant utilise DESCryptoServiceProvider (une implémentation de DES) avec la clé () spécifiée (Key) et le vecteur d’initialisation (IV) pour chiffrer un fichier spécifié par inName. Il génère ensuite le résultat chiffré dans le fichier spécifié par 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 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

Le déchiffrement peut être géré de la même façon ; utiliser CreateDecryptor au lieu de CreateEncryptor. Le même vecteur de clé (Key) et d’initialisation (IV) utilisé pour chiffrer le fichier doit être utilisé pour le déchiffrer.

Remarques

Cet algorithme prend en charge une longueur de clé de 64 bits.

Voir aussi

• Services de chiffrement