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CryptoProvider.Encrypt(Byte[]) Método

  • Referencia

Definición

Espacio de nombres:
System.Security.RightsManagement
Ensamblado:
WindowsBase.dll

Cifra texto no cifrado para obtener texto cifrado.

public:
 cli::array <System::Byte> ^ Encrypt(cli::array <System::Byte> ^ clearText);
public byte[] Encrypt (byte[] clearText);
member this.Encrypt : byte[] -> byte[]
Public Function Encrypt (clearText As Byte()) As Byte()

Parámetros

clearText
Byte[]

Contenido de texto no cifrado que se va a cifrar.

Devoluciones

Byte[]

Cifra texto cifrado del clearText proporcionado.

Excepciones

ArgumentNullException

clearText es null.

RightsManagementException

No se permite el cifrado.

Ejemplos

En el ejemplo siguiente se muestra cómo usar el Encrypt método para convertir datos de texto no cifrado en datos de texto cifrado.

WriteStatus("   Binding the author's UseLicense and");
WriteStatus("       obtaining the CryptoProvider.");
using (CryptoProvider cryptoProvider =
            authorsUseLicense.Bind(_secureEnv))
{
    WriteStatus("   Writing encrypted content.");
    using (Stream clearTextStream =
                File.OpenRead(contentFile) )
    {
        using (Stream cryptoTextStream =
                    File.OpenWrite(encryptedFile))
        {
            // Write the length of the source content file
            // as the first four bytes of the encrypted file.
            cryptoTextStream.Write(
                BitConverter.GetBytes(clearTextStream.Length),
                0, sizeof(Int32));

            // Allocate clearText buffer.
            byte[] clearTextBlock =
                new byte[cryptoProvider.BlockSize];

            // Encrypt clearText to cryptoText block by block.
            for(;;)
            {   // Read clearText block.
                int readCount = ReliableRead(
                                    clearTextStream,
                                    clearTextBlock, 0 ,
                                    cryptoProvider.BlockSize);
                // readCount of zero is end of data.
                if (readCount == 0)  break; // for

                // Encrypt clearText to cryptoText.
                byte[] cryptoTextBlock =
                    cryptoProvider.Encrypt(clearTextBlock);

                // Write cryptoText block.
                cryptoTextStream.Write(cryptoTextBlock, 0,
                                       cryptoTextBlock.Length);
            }
            WriteStatus("   Closing '" + encryptedFilename + "'.");
        }// end:using (Stream cryptoTextStream =
    }// end:using (Stream clearTextStream =
}// end:using (CryptoProvider cryptoProvider =
WriteStatus("   Done - Content encryption complete.");

WriteStatus("   Binding the author's UseLicense and")
WriteStatus("       obtaining the CryptoProvider.")
Using cryptoProvider As CryptoProvider = authorsUseLicense.Bind(_secureEnv)
    WriteStatus("   Writing encrypted content.")
    Using clearTextStream As Stream = File.OpenRead(contentFile)
        Using cryptoTextStream As Stream = File.OpenWrite(encryptedFile)
            ' Write the length of the source content file
            ' as the first four bytes of the encrypted file.
            Dim expression As Int32
            cryptoTextStream.Write(BitConverter.GetBytes(clearTextStream.Length), 0, Len(expression))

            ' Allocate clearText buffer.
            Dim clearTextBlock(cryptoProvider.BlockSize - 1) As Byte

            ' Encrypt clearText to cryptoText block by block.
            Do
                Dim readCount As Integer = ReliableRead(clearTextStream, clearTextBlock, 0, cryptoProvider.BlockSize)
                ' readCount of zero is end of data.
                If readCount = 0 Then ' for
                    Exit Do
                End If

                ' Encrypt clearText to cryptoText.
                Dim cryptoTextBlock() As Byte = cryptoProvider.Encrypt(clearTextBlock)

                ' Write cryptoText block.
                cryptoTextStream.Write(cryptoTextBlock, 0, cryptoTextBlock.Length)
            Loop
            WriteStatus("   Closing '" & encryptedFilename & "'.")
        End Using ' end:using (Stream cryptoTextStream =
    End Using ' end:using (Stream clearTextStream =
End Using ' end:using (CryptoProvider cryptoProvider =
WriteStatus("   Done - Content encryption complete.")

Comentarios

La longitud de bytes del clearText búfer debe ser un múltiplo de la propiedad de cifrado BlockSize .

El sistema de administración de derechos digitales usa el cifrado de bloques AES. Con AES, los bloques se cifran de forma independiente, de modo que dos bloques de texto no cifrado idéntico generan resultados de texto cifrado idénticos. Para minimizar posibles amenazas de descifrado del cifrado de bloques independiente, las aplicaciones deben emplear métodos para modificar el contenido, como la compresión, para evitar el cifrado de bloques de texto no cifrado idénticos.

Se aplica a

Consulte también