Rfc2898DeriveBytes.IterationCount Eigenschaft
Definition
Wichtig
Einige Informationen beziehen sich auf Vorabversionen, die vor dem Release ggf. grundlegend überarbeitet werden. Microsoft übernimmt hinsichtlich der hier bereitgestellten Informationen keine Gewährleistungen, seien sie ausdrücklich oder konkludent.
Ruft die Anzahl der Iterationen für die Operation ab oder legt diese fest.
public:
property int IterationCount { int get(); void set(int value); };public int IterationCount { get; set; }member this.IterationCount : int with get, setPublic Property IterationCount As IntegerEigenschaftswert
Die Anzahl der Iterationen für die Operation.
Ausnahmen
Die Iterationsanzahl ist kleiner als 1.
Beispiele
Im folgenden Beispiel wird gezeigt, wie die IterationCount Eigenschaft verwendet wird, um die Anzahl der Iterationen anzuzeigen, die in der Generierung des Schlüssels verwendet werden. Dieses Codebeispiel ist Teil eines größeren Beispiels, das für die Rfc2898DeriveBytes-Klasse bereitgestellt wird.
//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
Hinweise
Die Iterationsanzahl ist die Anzahl, in der ein Vorgang ausgeführt wird. Für diese Methode sollte die Anzahl größer als null sein. Die mindest empfohlene Anzahl von Iterationen beträgt 1000.