MACTripleDES クラスとは何？わかりやすく解説 Weblio辞書

.NET Framework クラスライブラリリファレンス

索引トップ用語の索引ランキング

MACTripleDES クラス

TripleDES を使用して、入力データ CryptoStream の MAC (Message Authentication Code) を計算します。

名前空間: System.Security.Cryptography
アセンブリ: mscorlib (mscorlib.dll 内)
構文

Visual Basic (宣言)

<ComVisibleAttribute(True)> _
Public Class MACTripleDES
    Inherits KeyedHashAlgorithm

Visual Basic (使用法)

Dim instance As MACTripleDES

[ComVisibleAttribute(true)] 
public class MACTripleDES : KeyedHashAlgorithm

C++

[ComVisibleAttribute(true)] 
public ref class MACTripleDES : public
 KeyedHashAlgorithm

/** @attribute ComVisibleAttribute(true) */ 
public class MACTripleDES extends KeyedHashAlgorithm

JScript

ComVisibleAttribute(true) 
public class MACTripleDES extends
 KeyedHashAlgorithm

解説

MAC を使用すると、送信者と受信者が共有キーを共有していれば、セキュリティ設定されていないチャネルを通して送信されたメッセージが不正に変更されていないかどうかを確認できます。送信者は元のデータの MAC を計算し、元のデータと MAC の両方を単一のメッセージとして送信します。受信者は受信メッセージの MAC を再計算して、計算した MAC が送信された MAC と一致するかどうかをチェックします。

メッセージの変更や正しい MAC の再生には共有キーが必要なため、データや MAC を少しでも変更すると不一致が発生します。したがって、コードが一致していれば、メッセージが認証されます。

MACTripleDES は、長さが 16 または 24 バイトのキーを使用し、長さが 8 バイトのハッシュシーケンスを生成します。

使用例

次のセクションでコード例を示します。TripleDES ハッシュアルゴリズムを使用して data の MAC を計算し、result に格納する例を次に示します。2 番目の例は、MACTripleDES クラスの各メンバを使用する方法を示しています。

例 1

この例では、定義済みの定数 DATA_SIZE があることを前提にしています。

Visual Basic

Dim data(DATA_SIZE) As Byte
Dim key(24) As Byte
       
Dim mac3des As New MACTripleDES(key)
       
Dim result As Byte() = mac3des.ComputeHash(data)

byte[] data = new byte[DATA_SIZE];
byte[] key = new byte[24];

MACTripleDES mac3des = new MACTripleDES(key);

byte[] result = mac3des.ComputeHash(data);

C++

array<Byte>^data = gcnew array<Byte>(DATA_SIZE);
array<Byte>^key = gcnew array<Byte>(24);
MACTripleDES^ mac3des = gcnew MACTripleDES( key );
array<Byte>^result = mac3des->ComputeHash( data );

ubyte data[] = new ubyte[dataSize];
ubyte key[] = new ubyte[24];
MACTripleDES mac3des = new MACTripleDES(key);
ubyte result[] = mac3des.ComputeHash(data);

例 2

Visual Basic

Imports System
Imports System.IO
Imports System.Text
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 = ""

        EncodeNothing()
        EncodeMessage()
        EncodeStream()

        tbxOutput.AppendText(vbCrLf + "This sample completed "
 + _
            "successfully; press Exit to continue.")
        tbxOutput.Cursor = Cursors.Default
    End Sub
    Private Sub EncodeNothing()
        Dim macTriple As New
 MACTripleDES

        macTriple.Initialize()

        Dim key(23) As Byte
        RandomNumberGenerator.Create().GetBytes(key)
        macTriple.Key = key
        
        Dim message(1023) As Byte
        macTriple.ComputeHash(message)
        SummarizeMAC(macTriple, "MACTripleDES after initialization.")
    End Sub
    ' Compute the hash for a MACTripleDES that has transformed a byte
 array.
    Private Sub EncodeMessage()
        Dim keyData(23) As Byte
        RandomNumberGenerator.Create().GetBytes(keyData)
        Dim macTriple As New
 MACTripleDES(keyData)
        Dim message As String
 = "Encoding is fun!"
        Dim encodedMessage() As Byte
 
        encodedMessage = EncodeBytes(Encoding.ASCII.GetBytes(message))
        macTriple.ComputeHash(encodedMessage)

        SummarizeMAC(macTriple, "MACTripleDES after encoding a
 message.")
    End Sub
    ' Transform the byte array using MacTripleDES,
    ' and then summarize its properties.
    Private Function EncodeBytes(ByVal
 sourceBytes() As Byte)
        Dim currentPosition As Int16 = 0

        Dim targetBytes(1023) As Byte
        Dim sourceByteLength As Int16 = sourceBytes.Length

        ' Create an encryptor with a random key and the TripleDES
        ' class name.
        Dim key(23) As Byte
        RandomNumberGenerator.Create().GetBytes(key)
        Dim tripleDesName As String
 = "System.Security.Cryptography.TripleDES"
        Dim macTriple As New
 MACTripleDES(tripleDesName, key)

        ' Retrieve the block size to read the bytes.
        Dim inputBlockSize As Integer
 = macTriple.InputBlockSize

        Try
            ' Determine if multiple blocks can be transformed.
            If (macTriple.CanTransformMultipleBlocks) Then
                Dim numBytesRead As Int16 =
 0

                While (sourceByteLength - currentPosition >=
 inputBlockSize)
                    ' Transform the bytes from the currentposition in
 the
                    ' sourceBytes array, writing the bytes to the 
                    ' targetBytes array.
                    numBytesRead = macTriple.TransformBlock( _
                        sourceBytes, _
                        currentPosition, _
                        inputBlockSize, _
                        targetBytes, _
                        currentPosition)

                    ' Advance the current position in the sourceBytes
 array.
                    currentPosition += numBytesRead
                End While

                ' Transform the final block of bytes.
                Dim finalBytes() As Byte
 = macTriple.TransformFinalBlock( _
                        sourceBytes, _
                        currentPosition, _
                        sourceByteLength - currentPosition)

                ' Copy the contents of the finalBytes array to the
                ' targetBytes array.
                finalBytes.CopyTo(targetBytes, currentPosition)
            End If
        Catch ex As Exception

            WriteLine("Caught unexpected exception:"
 + _
                    ex.ToString())
        End Try

        ' Determine if the current transform can be reused.
        If (Not macTriple.CanReuseTransform)
 Then
            ' Free up any used resources.
            macTriple.Clear()
        End If

        ' Find the length of valid bytes (those without zeros).
        Dim iEnum As System.Collections.IEnumerator
        iEnum = targetBytes.GetEnumerator()

        Dim i As Int16 = 0

        While (iEnum.MoveNext())
            If (iEnum.Current.ToString().Equals("0"))
 Then
                Exit While
            End If
            i = i + 1
        End While

        ' Compute the hash based on the valid bytes in the array.
        macTriple.ComputeHash(targetBytes, 0, i)

        SummarizeMAC(macTriple, "MACTripleDES after computing
 the hash " + _
            "for the specified region of the byte array.")

        ' Create a new array with the number of valid bytes.
        Dim returnedArray(i) As Byte
        For j As Int16 = 0 To
 i - 1 Step 1

            returnedArray(j) = targetBytes(j)
        Next j

        Return returnedArray
    End Function
    Private Sub EncodeStream()
        Dim keyData(23) As Byte
        RandomNumberGenerator.Create().GetBytes(keyData)
        Dim macTriple As New
 MACTripleDES(keyData)
        Dim filePath As String
        filePath = System.IO.Directory.GetCurrentDirectory() + "\members.txt"
        Try
            Dim fileStream As New
 FileStream( _
                filePath, _
                FileMode.Open, _
                FileAccess.Read)

            macTriple.ComputeHash(fileStream)

            SummarizeMAC(macTriple, _
                "MACTripleDES after encoding a file stream.")
        Catch ex As Exception

            WriteLine("Specified path was not found: "
 + filePath)
        End Try
    End Sub
    Private Sub SummarizeMAC( _
        ByVal macTriple As MACTripleDES, _
        ByVal description As String)
        Dim classDescription As String
 = macTriple.ToString()

        Dim computedHash() As Byte
 = macTriple.Hash

        Dim hashSize As Integer
 = macTriple.HashSize

        Dim outputBlockSize As Integer
 = macTriple.OutputBlockSize

        ' Retrieve the key used in the hash algorithm.
        Dim key() As Byte
 = macTriple.Key

        WriteLine(vbCrLf + "**********************************")
        WriteLine(classDescription)
        WriteLine(description)
        WriteLine("----------------------------------")
        WriteLine("The size of the computed hash : "
 + hashSize.ToString())
        WriteLine("The key used in the hash algorithm : "
 + _
            Encoding.ASCII.GetString(key))
        WriteLine("The value of the computed hash : "
 + _
            Encoding.ASCII.GetString(computedHash))
    End Sub
    ' Write the specified message and carriage return to the output
 textbox.
    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 = "MACTripleDES"
        Me.Panel2.ResumeLayout(False)
        Me.Panel1.ResumeLayout(False)
        Me.ResumeLayout(False)

    End Sub

#End Region
End Class

using System;
using System.IO;
using System.Text;
using System.Collections;
using System.Security.Cryptography;

namespace csMACTripleDES
{
    class Class1
    {
        [STAThread]
        static void Main(string[]
 args)
        {
            EncodeNothing();
            EncodeMessage();
            EncodeStream();

            Console.WriteLine("This sample completed successfully; " +
                "press Enter to exit.");
            Console.ReadLine();
        }

        // Compute the hash for an empty array; summarize the properties.
        private static void
 EncodeNothing()
        {
            MACTripleDES macTriple = new MACTripleDES();

            macTriple.Initialize();

            byte[] key = new byte[24];
            RandomNumberGenerator.Create().GetBytes(key);
            macTriple.Key = key;

            macTriple.ComputeHash(new byte[1024]);
            SummarizeMAC(macTriple, "MACTripleDES after initialization.");
        }

        // Compute the hash for a MACTripleDES that has transformed
 a
        // file stream.
        private static void
 EncodeStream()
        {
            byte[] keyData = new byte[24];
            RandomNumberGenerator.Create().GetBytes(keyData);
            MACTripleDES macTriple = new MACTripleDES(keyData);

            string filePath = (System.IO.Directory.GetCurrentDirectory()
 +
                "\\members.txt");
            try
            {
                FileStream fileStream =
                    new FileStream(filePath, FileMode.Open, FileAccess.Read);

                macTriple.ComputeHash(fileStream);

                SummarizeMAC(macTriple, 
                    "MACTripleDES after encoding a file stream.");
            }
            catch (FileNotFoundException ex)
            {
                Console.WriteLine("Specified path was not found: "
                    + filePath);
            }
        }

        // Compute the hash for a MACTripleDES that has transformed
 a
        // byte array.
        private static void
 EncodeMessage()
        {
            byte[] keyData = new byte[24];
            RandomNumberGenerator.Create().GetBytes(keyData);
            MACTripleDES macTriple = new MACTripleDES(keyData);

            string message = "Encoding is fun!";
            byte[] encodedMessage = 
                EncodeBytes(Encoding.ASCII.GetBytes(message));

            macTriple.ComputeHash(encodedMessage);

            SummarizeMAC(macTriple, "MACTripleDES after encoding a message.");
        }
        
        // Transform the byte array using MacTripleDES,
        // and then summarize its properties.
        private static byte[] EncodeBytes(byte[]
 sourceBytes)
        {
            int currentPosition = 0;
            byte[] targetBytes = new byte[1024];
            int sourceByteLength = sourceBytes.Length;

            // Create an encryptor with a random key and the TripleDES
            // class name.
            byte[] key = new byte[24];
            RandomNumberGenerator.Create().GetBytes(key);
            string tripleDesName = "System.Security.Cryptography.TripleDES";
            MACTripleDES macTriple = new MACTripleDES(tripleDesName,
 key);

            // Retrieve the block size to read the bytes.
            int inputBlockSize = macTriple.InputBlockSize;

            try
            {
                // Determine if multiple blocks can be transformed.
                if (macTriple.CanTransformMultipleBlocks)
                {
                    int numBytesRead = 0;
                    while (
                        sourceByteLength - currentPosition >= inputBlockSize)
                    {
                        // Transform the bytes from the currentposition
 in the
                        // sourceBytes array, writing the bytes to the
 
                        // targetBytes array.
                        numBytesRead = macTriple.TransformBlock(
                            sourceBytes,
                            currentPosition,
                            inputBlockSize,
                            targetBytes,
                            currentPosition);

                        // Advance the current position in the
                        // sourceBytes array.
                        currentPosition += numBytesRead;
                    }

                    // Transform the final block of bytes.
                    byte[] finalBytes = macTriple.TransformFinalBlock(
                        sourceBytes,
                        currentPosition,
                        sourceByteLength - currentPosition);

                    // Copy the contents of the finalBytes array to
 the
                    // targetBytes array.
                    finalBytes.CopyTo(targetBytes,currentPosition);
                }

            }
            catch(Exception ex)
            {
                Console.WriteLine("Caught unexpected exception:" + 
                    ex.ToString());
            }

            // Determine if the current transform can be reused.
            if (!macTriple.CanReuseTransform)
            {
                // Free up any used resources.
                macTriple.Clear();
            }

            // Find the length of valid bytes (those without zeros).
            IEnumerator enum1 = targetBytes.GetEnumerator();
            int i = 0;
            while (enum1.MoveNext())
            {
                if (enum1.Current.ToString().Equals("0"))
                {
                    break;
                } 
                i++;
            }

            // Compute the hash based on the valid bytes in the array.
            macTriple.ComputeHash(targetBytes,0,i);

            SummarizeMAC(macTriple, "MACTripleDES after computing the hash "
 +
                "for the specified region of the byte array.");

            // Create a new array with the number of valid bytes.
            byte[] returnedArray = new byte[i];
            for (int j=0; j<i; j++) 
            {
                returnedArray[j] = targetBytes[j];
            }

            return returnedArray;
        }

        // Write a summary of the specified MACTripleDES to the console.
        private static void
 SummarizeMAC(
            MACTripleDES macTriple, 
            string description)
        {
            string classDescription = macTriple.ToString();

            byte[] computedHash = macTriple.Hash;

            int hashSize = macTriple.HashSize;

            int outputBlockSize = macTriple.OutputBlockSize;

            // Retrieve the key used in the hash algorithm.
            byte[] key = macTriple.Key;

            Console.WriteLine("\n**********************************");
            Console.WriteLine(classDescription);
            Console.WriteLine(description);
            Console.WriteLine("----------------------------------");
            Console.WriteLine("The size of the computed hash : " + hashSize);
            Console.WriteLine("The key used in the hash algorithm
 : " + 
                Encoding.ASCII.GetString(key));
            Console.WriteLine("The value of the computed hash : " + 
                Encoding.ASCII.GetString(computedHash));
        }
    }
}

C++

using namespace System;
using namespace System::IO;
using namespace System::Text;
using namespace System::Collections;
using namespace System::Security::Cryptography;

namespace CryptographySample
{
    ref class DESSample
    {
    public:

        static void TestDES();

    private:
        static void EncodeNothing();
        static void EncodeStream();
        static void EncodeMessage();
        static array<Byte>^ EncodeBytes(array<Byte>^
 sourceBytes);
        static void SummarizeMAC(MACTripleDES^
 macTriple, 
            String^ description);
    };

    void DESSample::TestDES()
    {
        EncodeNothing();
        EncodeMessage();
        EncodeStream();
        Console::WriteLine("This sample completed successfully; "
            "press Enter to exit.");
        Console::ReadLine();
    }

    // Compute the hash for an empty array; summarize the properties.
    void DESSample::EncodeNothing()
    {
        MACTripleDES^ macTriple = gcnew MACTripleDES;

        macTriple->Initialize();

        array<Byte>^ key = gcnew array<Byte>(24);
        RandomNumberGenerator::Create()->GetBytes(key);
        macTriple->Key = key;
        macTriple->ComputeHash(gcnew array<Byte>(1024));
        SummarizeMAC(macTriple, "MACTripleDES after initialization.");
    }

    // Compute the hash for a MACTripleDES that has transformed a
    // file stream.
    void DESSample::EncodeStream()
    {
        array<Byte>^ keyData = gcnew array<Byte>(24);
        RandomNumberGenerator::Create()->GetBytes(keyData);
        MACTripleDES^ macTriple = gcnew MACTripleDES(keyData);

        String^ filePath = (String::Concat(
            System::IO::Directory::GetCurrentDirectory(), 
            "\\members.txt"));
        try
        {
            FileStream fileStream(filePath,
                FileMode::Open, FileAccess::Read);

            macTriple->ComputeHash(%fileStream);

            SummarizeMAC(macTriple, 
                "MACTripleDES after encoding a file stream.");
        }
        catch (FileNotFoundException^ ex) 
        {
            Console::WriteLine("Specified path was not found: {0}", 
                filePath);
            __assume(ex);
        }

    }


    // Compute the hash for a MACTripleDES that has transformed a
    // byte array.
    void DESSample::EncodeMessage()
    {
        Encoding^ encodingASCII = Encoding::ASCII;
        array<Byte>^ keyData = gcnew array<Byte>(24);
        RandomNumberGenerator::Create()->GetBytes(keyData);
        MACTripleDES^ macTriple = gcnew MACTripleDES(keyData);

        String^ message = "Encoding is fun!";
        array<Byte>^ encodedMessage = EncodeBytes(
            encodingASCII->GetBytes(message));
        macTriple->ComputeHash(encodedMessage);

        SummarizeMAC(macTriple, 
            "MACTripleDES after encoding a message.");
    }


    // Transform the byte array using MacTripleDES,
    // and then summarize its properties.
    array<Byte>^ DESSample::EncodeBytes(array<Byte>^ sourceBytes)
    {
        int currentPosition = 0;
        array<Byte>^ targetBytes = gcnew array<Byte>(1024);
        int sourceByteLength = sourceBytes->Length;

        // Create an encryptor with a random key and the TripleDES
        // class name.
        array<Byte>^ key = gcnew array<Byte>(24);
        RandomNumberGenerator::Create()->GetBytes(key);
        String^ tripleName = "System.Security.Cryptography.TripleDES";
        MACTripleDES^ macTriple = gcnew MACTripleDES(tripleName, key);

        // Retrieve the block size to read the bytes.
        int inputBlockSize = macTriple->InputBlockSize;

        try
        {

            // Determine if multiple blocks can be transformed.
            if (macTriple->CanTransformMultipleBlocks)
            {
                int bytesRead = 0;
                while (sourceByteLength - currentPosition >=
 
                    inputBlockSize)
                {
                    // Transform the bytes from the currentposition
 in 
                    // the sourceBytes array, writing the bytes to the
 
                    // targetBytes array.
                    bytesRead = 
                        macTriple->TransformBlock(sourceBytes, 
                        currentPosition, inputBlockSize, targetBytes, 
                        currentPosition);
                    // Advance the current position in the
                    // sourceBytes array.
                    currentPosition += bytesRead;
                }

                // Transform the final block of bytes.
                array<Byte>^ finalBytes = 
                    macTriple->TransformFinalBlock(sourceBytes, 
                    currentPosition, sourceByteLength - 
                    currentPosition);
                // Copy the contents of the finalBytes array to the
                // targetBytes array.
                finalBytes->CopyTo(targetBytes, currentPosition);
            }
        }
        catch (ArgumentException^ ex) 
        {
            Console::WriteLine("Caught unexpected exception:{0}", ex);
        }

        // Determine if the current transform can be reused.
        if (!macTriple->CanReuseTransform)
        {
            // Free up any used resources.
            macTriple->Clear();
        }

        // Find the length of valid bytes (those without zeros).
        int i = 0;
        for each (Byte byte in targetBytes)
        {
            if (byte == 0)
                break;
            i++;
        }

        // Compute the hash based on the valid bytes in the array.
        macTriple->ComputeHash(targetBytes, 0, i);

        SummarizeMAC(macTriple, "MACTripleDES after computing "
            "the hash for the specified region of the byte
 array.");

        // Create a new array with the number of valid bytes.
        array<Byte>^ returnedArray = gcnew array<Byte>(i);
        Array::Copy(targetBytes, returnedArray, i);
        return returnedArray;
    }


    // Write a summary of the specified MACTripleDES to the console.
    void DESSample::SummarizeMAC(MACTripleDES^ macTriple, 
        String^ description)
    {
        Encoding^ encASCIIEncoding = Encoding::ASCII;

        String^ classDescription = macTriple->ToString();

        array<Byte>^ computedHash = macTriple->Hash;

        int hashSize = macTriple->HashSize;

        int outputBlockSize = macTriple->OutputBlockSize;

        // Retrieve the key used in the hash algorithm.
        array<Byte>^ key = macTriple->Key;

        Console::WriteLine("\n**********************************");
        Console::WriteLine(classDescription);
        Console::WriteLine(description);
        Console::WriteLine("----------------------------------");
        Console::WriteLine("The size of the computed hash : {0}", 
            hashSize);
        Console::WriteLine("The key used in the hash algorithm
 : {0}", 
            encASCIIEncoding->GetString(key));
        Console::WriteLine("The value of the computed hash : {0}", 
            encASCIIEncoding->GetString(computedHash));
    }
}

using namespace CryptographySample;

int main()
{
    DESSample::TestDES();
}

//
// This sample produces the following output:
//
// **********************************
// System.Security.Cryptography.MACTripleDES
// MACTripleDES after initialization.
// ----------------------------------
// The size of the computed hash : 64
// The key used in the hash algorithm : +Lnf>j%?4?7?V???K?Jv_AcB
// The value of the computed hash : YH>|*DX;
// 
// **********************************
// System.Security.Cryptography.MACTripleDES
// MACTripleDES after computing the hash for the specified region 
// of the byte array.
// ----------------------------------
// The size of the computed hash : 64
// The key used in the hash algorithm : >
// -?h?v?tF*r`f%V?t`.jS50
// The value of the computed hash : :?9q1$b?
// 
// **********************************
// System.Security.Cryptography.MACTripleDES
// MACTripleDES after encoding a message.
// ----------------------------------
// The size of the computed hash : 64
// The key used in the hash algorithm : ?rK>~6>?xy-R? r7s,_kCP{}
// The value of the computed hash : bG?*UO?S
// 
// **********************************
// System.Security.Cryptography.MACTripleDES
// MACTripleDES after encoding a file stream.
// ----------------------------------
// The size of the computed hash : 64
// Yv)???rTY?}?T?/\FOI?D$sh algorithm :
// The value of the computed hash : K??T]QgN
// This sample completed successfully; press Enter to exit.

import System.*;
import System.IO.*;
import System.Text.*;
import System.Collections.*;
import System.Security.Cryptography.*;

class Class1
{
    /** @attribute STAThread()
     */
    public static void main(String[]
 args)
    {
        EncodeNothing();
        EncodeMessage();
        EncodeStream();
        Console.WriteLine("This sample completed successfully; " 
            + "press Enter to exit.");
        Console.ReadLine();
    } //main

    // Compute the hash for an empty array; summarize the properties.
    private static void
 EncodeNothing()
    {
        MACTripleDES macTriple = new MACTripleDES();

        macTriple.Initialize();

        ubyte key[] = new ubyte[24];
        RandomNumberGenerator.Create().GetBytes(key);
        macTriple.set_Key(key);
        macTriple.ComputeHash(new ubyte[1024]);
        SummarizeMAC(macTriple, "MACTripleDES after initialization.");
    } //EncodeNothing

    // Compute the hash for a MACTripleDES that has transformed a
    // file stream.
    private static void
 EncodeStream()
    {
        ubyte keyData[] = new ubyte[24];
        RandomNumberGenerator.Create().GetBytes(keyData);
        MACTripleDES macTriple = new MACTripleDES(keyData);

        String filePath = System.IO.Directory.GetCurrentDirectory() 
            + "\\members.txt";
        try {
            FileStream fileStream = new FileStream(filePath, FileMode.Open,
 
                FileAccess.Read);
            macTriple.ComputeHash(fileStream);
            SummarizeMAC(macTriple, 
                "MACTripleDES after encoding a file stream.");
        }
        catch (FileNotFoundException ex) {
            Console.WriteLine("Specified path was not found: " + filePath);
        }
    } //EncodeStream

    // Compute the hash for a MACTripleDES that has transformed a
    // byte array.
    private static void
 EncodeMessage()
    {
        ubyte keyData[] = new ubyte[24];
        RandomNumberGenerator.Create().GetBytes(keyData);
        MACTripleDES macTriple = new MACTripleDES(keyData);
        String message = "Encoding is fun!";
        ubyte encodedMessage[] = EncodeBytes(Encoding.get_ASCII().
            GetBytes(message));
        macTriple.ComputeHash(encodedMessage);
        SummarizeMAC(macTriple, "MACTripleDES after encoding a message.");
    } //EncodeMessage

    // Transform the byte array using MacTripleDES,
    // and then summarize its properties.
    private static ubyte[] EncodeBytes(ubyte
 sourceBytes[])
    {
        int currentPosition = 0;
        ubyte targetBytes[] = new ubyte[1024];
        int sourceByteLength = sourceBytes.get_Length();
        // Create an encryptor with a random key and the TripleDES
        // class name.
        ubyte key[] = new ubyte[24];
        RandomNumberGenerator.Create().GetBytes(key);
        String tripleDesName = "System.Security.Cryptography.TripleDES";
        MACTripleDES macTriple = new MACTripleDES(tripleDesName,
 key);

        // Retrieve the block size to read the bytes.
        int inputBlockSize = macTriple.get_InputBlockSize();
        try {
            // Determine if multiple blocks can be transformed.
            if (macTriple.get_CanTransformMultipleBlocks()) {
                int numBytesRead = 0;
                while (sourceByteLength - currentPosition >=
 inputBlockSize) {
                    // Transform the bytes from the currentposition
 in the
                    // sourceBytes array, writing the bytes to the 
                    // targetBytes array.
                    numBytesRead = macTriple.TransformBlock(sourceBytes, 
                        currentPosition, inputBlockSize, targetBytes, 
                        currentPosition);
                    // Advance the current position in the
                    // sourceBytes array.
                    currentPosition += numBytesRead;
                }
                // Transform the final block of bytes.
                ubyte finalBytes[] = macTriple.TransformFinalBlock(sourceBytes, 
                    currentPosition, sourceByteLength - currentPosition);
                // Copy the contents of the finalBytes array to the
                // targetBytes array.
                finalBytes.CopyTo(targetBytes, currentPosition);
            }
        }
        catch (System.Exception ex) {
            Console.WriteLine("Caught unexpected exception:" + ex.ToString());
        }
        // Determine if the current transform can be reused.
        if (!(macTriple.get_CanReuseTransform())) {
            // Free up any used resources.
            macTriple.Clear();
        }
        // Find the length of valid bytes (those without zeros).
        IEnumerator enum1 = targetBytes.GetEnumerator();
        int i = 0;
        while (enum1.MoveNext()) {
            if (enum1.get_Current().ToString().Equals("0"))
 {
                break;
            }
            i++;
        }
        // Compute the hash based on the valid bytes in the array.
        macTriple.ComputeHash(targetBytes, 0, i);

        SummarizeMAC(macTriple, "MACTripleDES after computing the hash "
 
            + "for the specified region of the byte array.");
        // Create a new array with the number of valid bytes.
        ubyte returnedArray[] = new ubyte[i];
        for (int j = 0; j < i; j++) {
            returnedArray.set_Item(j, targetBytes.get_Item(j));
        }
        return returnedArray;
    } //EncodeBytes

    // Write a summary of the specified MACTripleDES to the console.
    private static void
 SummarizeMAC(MACTripleDES macTriple, 
        String description)
    {
        String classDescription = macTriple.ToString();

        ubyte computedHash[] = macTriple.get_Hash();

        int hashSize = macTriple.get_HashSize();

        int outputBlockSize = macTriple.get_OutputBlockSize();

        // Retrieve the key used in the hash algorithm.
        ubyte key[] = macTriple.get_Key();

        Console.WriteLine("\n**********************************");
        Console.WriteLine(classDescription);
        Console.WriteLine(description);
        Console.WriteLine("----------------------------------");
        Console.WriteLine("The size of the computed hash : " + hashSize);
        Console.WriteLine("The key used in the hash algorithm
 : " 
            + Encoding.get_ASCII().GetString(key));
        Console.WriteLine("The value of the computed hash : " 
            + Encoding.get_ASCII().GetString(computedHash));
    } //SummarizeMAC
} //Class1

継承階層

System.Object
   System.Security.Cryptography.HashAlgorithm
     System.Security.Cryptography.KeyedHashAlgorithm
      System.Security.Cryptography.MACTripleDES

スレッドセーフ

この型の public static (Visual Basic では Shared) メンバはすべて、スレッドセーフです。インスタンスメンバの場合は、スレッドセーフであるとは限りません。