DESCryptoServiceProvider Classe

Definição

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

Herança

Object

SymmetricAlgorithm

DES

DESCryptoServiceProvider

Atributos

ComVisibleAttribute

Exemplos

O exemplo de código seguinte usa DESCryptoServiceProvider (uma implementação de DES) com a chave especificada (Key) e o vetor de inicialização (IV) para encriptar um ficheiro especificado por inName. De seguida, o resultado encriptado é enviado para o ficheiro especificado por 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

A desencriptação pode ser tratada da mesma forma; usar CreateDecryptor em vez de CreateEncryptor. A mesma chave (Key) e vetor de inicialização (IV) usados para encriptar o ficheiro devem ser usados para o desencriptar.

Observações

Este algoritmo suporta um comprimento de chave de 64 bits.

Ver também

• Serviços de criptografia