Rfc2898DeriveBytes.IterationCount Propiedad

Definición

Espacio de nombres:

System.Security.Cryptography

Ensamblado:

System.Security.Cryptography.dll

Source:

Rfc2898DeriveBytes.cs

Obtiene o establece el número de iteraciones de la operación.

public:
 property int IterationCount { int get(); void set(int value); };

public int IterationCount { get; set; }

member this.IterationCount : int with get, set

Public Property IterationCount As Integer

Valor de propiedad

Int32

Número de iteraciones de la operación.

Excepciones

ArgumentOutOfRangeException

El número de iteraciones es menor que 1.

Ejemplos

En el ejemplo siguiente se muestra cómo usar la IterationCount propiedad para mostrar el número de iteraciones usadas en la generación de la clave. Este ejemplo de código es parte de un ejemplo más grande proporcionado para la clase Rfc2898DeriveBytes.

//The default iteration count is 1000 so the two methods use the same iteration count.
int myIterations = 1000;

try
{
   Rfc2898DeriveBytes ^ k1 = gcnew Rfc2898DeriveBytes( pwd1,salt1,myIterations );
   Rfc2898DeriveBytes ^ k2 = gcnew Rfc2898DeriveBytes( pwd1,salt1 );

   // Encrypt the data.
   Aes^ encAlg = Aes::Create();
   encAlg->Key = k1->GetBytes( 16 );
   MemoryStream^ encryptionStream = gcnew MemoryStream;
   CryptoStream^ encrypt = gcnew CryptoStream( encryptionStream,encAlg->CreateEncryptor(),CryptoStreamMode::Write );
   array<Byte>^utfD1 = (gcnew System::Text::UTF8Encoding( false ))->GetBytes( data1 );

   encrypt->Write( utfD1, 0, utfD1->Length );
   encrypt->FlushFinalBlock();
   encrypt->Close();
   array<Byte>^edata1 = encryptionStream->ToArray();
   k1->Reset();

   // Try to decrypt, thus showing it can be round-tripped.
   Aes^ decAlg = Aes::Create();
   decAlg->Key = k2->GetBytes( 16 );
   decAlg->IV = encAlg->IV;
   MemoryStream^ decryptionStreamBacking = gcnew MemoryStream;
   CryptoStream^ decrypt = gcnew CryptoStream( decryptionStreamBacking,decAlg->CreateDecryptor(),CryptoStreamMode::Write );

   decrypt->Write( edata1, 0, edata1->Length );
   decrypt->Flush();
   decrypt->Close();
   k2->Reset();

   String^ data2 = (gcnew UTF8Encoding( false ))->GetString( decryptionStreamBacking->ToArray() );
   if (  !data1->Equals( data2 ) )
   {
      Console::WriteLine( "Error: The two values are not equal." );
   }
   else
   {
      Console::WriteLine( "The two values are equal." );
      Console::WriteLine( "k1 iterations: {0}", k1->IterationCount );
      Console::WriteLine( "k2 iterations: {0}", k2->IterationCount );
   }

            //The default iteration count is 1000 so the two methods use the same iteration count.
            int myIterations = 1000;
            try
            {
                Rfc2898DeriveBytes k1 = new Rfc2898DeriveBytes(pwd1, salt1,
myIterations);
                Rfc2898DeriveBytes k2 = new Rfc2898DeriveBytes(pwd1, salt1);
                // Encrypt the data.
                Aes encAlg = Aes.Create();
                encAlg.Key = k1.GetBytes(16);
                MemoryStream encryptionStream = new MemoryStream();
                CryptoStream encrypt = new CryptoStream(encryptionStream,
encAlg.CreateEncryptor(), CryptoStreamMode.Write);
                byte[] utfD1 = new System.Text.UTF8Encoding(false).GetBytes(
data1);

                encrypt.Write(utfD1, 0, utfD1.Length);
                encrypt.FlushFinalBlock();
                encrypt.Close();
                byte[] edata1 = encryptionStream.ToArray();
                k1.Reset();

                // Try to decrypt, thus showing it can be round-tripped.
                Aes decAlg = Aes.Create();
                decAlg.Key = k2.GetBytes(16);
                decAlg.IV = encAlg.IV;
                MemoryStream decryptionStreamBacking = new MemoryStream();
                CryptoStream decrypt = new CryptoStream(
decryptionStreamBacking, decAlg.CreateDecryptor(), CryptoStreamMode.Write);
                decrypt.Write(edata1, 0, edata1.Length);
                decrypt.Flush();
                decrypt.Close();
                k2.Reset();
                string data2 = new UTF8Encoding(false).GetString(
decryptionStreamBacking.ToArray());

                if (!data1.Equals(data2))
                {
                    Console.WriteLine("Error: The two values are not equal.");
                }
                else
                {
                    Console.WriteLine("The two values are equal.");
                    Console.WriteLine("k1 iterations: {0}", k1.IterationCount);
                    Console.WriteLine("k2 iterations: {0}", k2.IterationCount);
                }

'The default iteration count is 1000 so the two methods use the same iteration count.
Dim myIterations As Integer = 1000
Try
    Dim k1 As New Rfc2898DeriveBytes(pwd1, salt1, myIterations)
    Dim k2 As New Rfc2898DeriveBytes(pwd1, salt1)
    ' Encrypt the data.
    Dim encAlg As Aes = Aes.Create()
    encAlg.Key = k1.GetBytes(16)
    Dim encryptionStream As New MemoryStream()
    Dim encrypt As New CryptoStream(encryptionStream, encAlg.CreateEncryptor(), CryptoStreamMode.Write)
    Dim utfD1 As Byte() = New System.Text.UTF8Encoding(False).GetBytes(data1)
    encrypt.Write(utfD1, 0, utfD1.Length)
    encrypt.FlushFinalBlock()
    encrypt.Close()
    Dim edata1 As Byte() = encryptionStream.ToArray()
    k1.Reset()

    ' Try to decrypt, thus showing it can be round-tripped.
    Dim decAlg As Aes = Aes.Create()
    decAlg.Key = k2.GetBytes(16)
    decAlg.IV = encAlg.IV
    Dim decryptionStreamBacking As New MemoryStream()
    Dim decrypt As New CryptoStream(decryptionStreamBacking, decAlg.CreateDecryptor(), CryptoStreamMode.Write)
    decrypt.Write(edata1, 0, edata1.Length)
    decrypt.Flush()
    decrypt.Close()
    k2.Reset()
    Dim data2 As String = New UTF8Encoding(False).GetString(decryptionStreamBacking.ToArray())

    If Not data1.Equals(data2) Then
        Console.WriteLine("Error: The two values are not equal.")
    Else
        Console.WriteLine("The two values are equal.")
        Console.WriteLine("k1 iterations: {0}", k1.IterationCount)
        Console.WriteLine("k2 iterations: {0}", k2.IterationCount)
    End If

Comentarios

El recuento de iteraciones es el número de veces que se realiza una operación. Para este método, el recuento debe ser mayor que cero. El número mínimo recomendado de iteraciones es 1000.

Consulte también

• servicios criptográficos