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KeySizes Class

Determines the set of valid key sizes for the symmetric cryptographic algorithms.

Namespace: System.Security.Cryptography
Assembly: mscorlib (in mscorlib.dll)

'Declaration
<ComVisibleAttribute(True)> _
Public NotInheritable Class KeySizes
'Usage
Dim instance As KeySizes

/** @attribute ComVisibleAttribute(true) */ 
public final class KeySizes
ComVisibleAttribute(true) 
public final class KeySizes

The following example shows the use of members of the KeySizes class.

Imports System
Imports System.Security.Cryptography

Public Class Form1
    Inherits System.Windows.Forms.Form

    ' Event handler for Run button.
    Private Sub Button1_Click( _
        ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles Button1.Click

        tbxOutput.Cursor = Cursors.WaitCursor
        tbxOutput.Text = ""

        ' Initializes a new instance of the KeySizes class with the
        ' specified key values.
        Dim MinSize As Integer = 64
        Dim MaxSize As Integer = 1024
        Dim SkipSize As Integer = 64
        Dim keySizes As New KeySizes(MinSize, MaxSize, SkipSize)

        ' Show the values of the keys.
        ShowKeys(New KeySizes(0) {keySizes}, "Custom Keys")

        ' Create a new symmetric algorithm and display its key values.
        Dim rijn As SymmetricAlgorithm = SymmetricAlgorithm.Create()
        WriteLine("rijn.blocksize:" + rijn.BlockSize.ToString())
        ShowKeys(rijn.LegalKeySizes, rijn.ToString())

        ' Create a new RSA algorithm and display its key values.
        Dim rsaCSP As New RSACryptoServiceProvider(384)
        WriteLine("RSACryptoServiceProvider KeySize = " + _
            rsaCSP.KeySize.ToString())
        ShowKeys(rsaCSP.LegalKeySizes, rsaCSP.ToString())

        ' Reset the cursor and conclude application.
        WriteLine("This sample completed successfully;" + _
            " press Exit to continue.")
        tbxOutput.Cursor = Cursors.Default
    End Sub

    ' Display specified KeySize properties to output textbox.
    Private Sub ShowKeys( _
        ByVal KeySizes() As KeySizes, _
        ByVal objectName As String)

        ' Retrieve the first KeySizes in the array.
        Dim firstKeySize As KeySizes = KeySizes(0)

        ' Retrieve the minimum key size in bits.
        Dim minKeySize As Integer = firstKeySize.MinSize

        ' Retrieve the maximum key size in bits.
        Dim maxKeySize As Integer = firstKeySize.MaxSize

        ' Retrieve the interval between valid key size in bits.
        Dim skipKeySize As Integer = firstKeySize.SkipSize

        WriteLine("KeySizes retrieved from the " + objectName + " object.")
        WriteLine("Minimum key size bits: " + minKeySize.ToString())
        WriteLine("Maximum key size bits: " + maxKeySize.ToString())
        WriteLine("Interval between key size bits: " + skipKeySize.ToString())
        WriteLine("")
    End Sub
    ' Display the message to the textbox with a carriage return and line feed.
    Private Sub WriteLine(ByVal message As String)
        tbxOutput.AppendText(message + vbCrLf)
    End Sub
    ' Event handler for Exit button.
    Private Sub Button2_Click( _
        ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles Button2.Click

        Application.Exit()
    End Sub
#Region " Windows Form Designer generated code "

    Public Sub New()
        MyBase.New()

        'This call is required by the Windows Form Designer.
        InitializeComponent()

        'Add any initialization after the InitializeComponent() call

    End Sub

    'Form overrides dispose to clean up the component list.
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If Not (components Is Nothing) Then
                components.Dispose()
            End If
        End If
        MyBase.Dispose(disposing)
    End Sub

    'Required by the Windows Form Designer
    Private components As System.ComponentModel.IContainer

    'NOTE: The following procedure is required by the Windows Form Designer
    'It can be modified using the Windows Form Designer.  
    'Do not modify it using the code editor.
    Friend WithEvents Panel2 As System.Windows.Forms.Panel
    Friend WithEvents Panel1 As System.Windows.Forms.Panel
    Friend WithEvents Button1 As System.Windows.Forms.Button
    Friend WithEvents Button2 As System.Windows.Forms.Button
    Friend WithEvents tbxOutput As System.Windows.Forms.RichTextBox
    <System.Diagnostics.DebuggerStepThrough()> _
    Private Sub InitializeComponent()
        Me.Panel2 = New System.Windows.Forms.Panel
        Me.Button1 = New System.Windows.Forms.Button
        Me.Button2 = New System.Windows.Forms.Button
        Me.Panel1 = New System.Windows.Forms.Panel
        Me.tbxOutput = New System.Windows.Forms.RichTextBox
        Me.Panel2.SuspendLayout()
        Me.Panel1.SuspendLayout()
        Me.SuspendLayout()
        '
        'Panel2
        '
        Me.Panel2.Controls.Add(Me.Button1)
        Me.Panel2.Controls.Add(Me.Button2)
        Me.Panel2.Dock = System.Windows.Forms.DockStyle.Bottom
        Me.Panel2.DockPadding.All = 20
        Me.Panel2.Location = New System.Drawing.Point(0, 320)
        Me.Panel2.Name = "Panel2"
        Me.Panel2.Size = New System.Drawing.Size(616, 64)
        Me.Panel2.TabIndex = 1
        '
        'Button1
        '
        Me.Button1.Dock = System.Windows.Forms.DockStyle.Right
        Me.Button1.Font = New System.Drawing.Font("Microsoft Sans Serif", _
            9.0!, _
            System.Drawing.FontStyle.Regular, _
            System.Drawing.GraphicsUnit.Point, _
            CType(0, Byte))
        Me.Button1.Location = New System.Drawing.Point(446, 20)
        Me.Button1.Name = "Button1"
        Me.Button1.Size = New System.Drawing.Size(75, 24)
        Me.Button1.TabIndex = 2
        Me.Button1.Text = "&Run"
        '
        'Button2
        '
        Me.Button2.Dock = System.Windows.Forms.DockStyle.Right
        Me.Button2.Font = New System.Drawing.Font("Microsoft Sans Serif", _
            9.0!, _
            System.Drawing.FontStyle.Regular, _
            System.Drawing.GraphicsUnit.Point, _
            CType(0, Byte))
        Me.Button2.Location = New System.Drawing.Point(521, 20)
        Me.Button2.Name = "Button2"
        Me.Button2.Size = New System.Drawing.Size(75, 24)
        Me.Button2.TabIndex = 3
        Me.Button2.Text = "E&xit"
        '
        'Panel1
        '
        Me.Panel1.Controls.Add(Me.tbxOutput)
        Me.Panel1.Dock = System.Windows.Forms.DockStyle.Fill
        Me.Panel1.DockPadding.All = 20
        Me.Panel1.Location = New System.Drawing.Point(0, 0)
        Me.Panel1.Name = "Panel1"
        Me.Panel1.Size = New System.Drawing.Size(616, 320)
        Me.Panel1.TabIndex = 2
        '
        'tbxOutput
        '
        Me.tbxOutput.AccessibleDescription = _
            "Displays output from application."
        Me.tbxOutput.AccessibleName = "Output textbox."
        Me.tbxOutput.Dock = System.Windows.Forms.DockStyle.Fill
        Me.tbxOutput.Location = New System.Drawing.Point(20, 20)
        Me.tbxOutput.Name = "tbxOutput"
        Me.tbxOutput.Size = New System.Drawing.Size(576, 280)
        Me.tbxOutput.TabIndex = 1
        Me.tbxOutput.Text = "Click the Run button to run the application."
        '
        'Form1
        '
        Me.AutoScaleBaseSize = New System.Drawing.Size(6, 15)
        Me.ClientSize = New System.Drawing.Size(616, 384)
        Me.Controls.Add(Me.Panel1)
        Me.Controls.Add(Me.Panel2)
        Me.Name = "Form1"
        Me.Text = "KeySizes"
        Me.Panel2.ResumeLayout(False)
        Me.Panel1.ResumeLayout(False)
        Me.ResumeLayout(False)

    End Sub

#End Region
End Class
'
' This sample produces the following output:
'
' KeySizes retrieved from the Custom Keys object.
' Minimum key size bits: 64
' Maximum key size bits: 1024
' Interval between key size bits: 64
' 
' rijn.blocksize:128
' KeySizes retrieved from the System.Security.Cryptography.RijndaelManaged
' object.
' Minimum key size bits: 128
' Maximum key size bits: 256
' Interval between key size bits: 64
' 
' RSACryptoServiceProvider KeySize = 384
' KeySizes retrieved from the
' System.Security.Cryptography.RSACryptoServiceProvider object.
' Minimum key size bits: 384
' Maximum key size bits: 16384
' Interval between key size bits: 8
' 
' This sample completed successfully; press Exit to continue.

import System.*;
import System.Security.Cryptography.*;

class KeySizesMembers
{
    /** @attribute STAThread()
     */
    public static void main(String[] args)
    {
        // Initializes a new instance of the KeySizes class with the
        // specified key values.
        int minSize = 64;
        int maxSize = 1024;
        int skipSize = 64;
        KeySizes keySizes = new KeySizes(minSize, maxSize, skipSize);

        // Show the values of the keys.
        ShowKeys(new KeySizes[] { keySizes }, "Custom Keys");
        // Create a new symmetric algorithm and display its key values.
        SymmetricAlgorithm rijn = SymmetricAlgorithm.Create();
        ShowKeys(rijn.get_LegalKeySizes(), rijn.ToString());
        Console.WriteLine("rijn.blocksize:" + rijn.get_BlockSize());
        // Create a new RSA algorithm and display its key values.
        RSACryptoServiceProvider rsaCSP = new RSACryptoServiceProvider(384);
        ShowKeys(rsaCSP.get_LegalKeySizes(), rsaCSP.ToString());
        Console.WriteLine("RSACryptoServiceProvider KeySize = " 
            + rsaCSP.get_KeySize());
        Console.WriteLine("This sample completed successfully; " 
            + "press Enter to exit.");
        Console.ReadLine();
    } //main

    // Display specified KeySize properties to the console.
    private static void ShowKeys(KeySizes keySizes[], String objectName)
    {
        // Retrieve the first KeySizes in the array.
        KeySizes firstKeySize = (KeySizes)keySizes.get_Item(0);
        // Retrieve the minimum key size in bits.
        int minKeySize = firstKeySize.get_MinSize();

        // Retrieve the maximum key size in bits.
        int maxKeySize = firstKeySize.get_MaxSize();

        // Retrieve the interval between valid key size in bits.
        int skipKeySize = firstKeySize.get_SkipSize();

        Console.Write("\n KeySizes retrieved from the ");
        Console.WriteLine(objectName + " object.");
        Console.WriteLine("Minimum key size bits: " + minKeySize);
        Console.WriteLine("Maximum key size bits: " + maxKeySize);
        Console.WriteLine("Interval between key size bits: " + skipKeySize);
    } //ShowKeys
} //KeySizesMembers
//
// This sample produces the following output:
//
// KeySizes retrieved from the Custom Keys object.
// Minimum key size bits: 64
// Maximum key size bits: 1024
// Interval between key size bits: 64
// 
// KeySizes retrieved from the System.Security.Cryptography.RijndaelManaged
// object.
// Minimum key size bits: 128
// Maximum key size bits: 256
// Interval between key size bits: 64
// rijn.blocksize:128
// 
// KeySizes retrieved from the
// System.Security.Cryptography.RSACryptoServiceProvider object.
// Minimum key size bits: 384
// Maximum key size bits: 16384
// Interval between key size bits: 8
// RSACryptoServiceProvider KeySize = 384
// This sample completed successfully; press Enter to exit.

System.Object
  System.Security.Cryptography.KeySizes

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0

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