DESCryptoServiceProvider クラス (System.Security.Cryptography)

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言語フィルタ

このページは次のバージョンについて記述しています。

Microsoft Visual Studio 2008/.NET Framework 3.5

その他のバージョンについては、以下の情報を参照してください。

.NET Framework クラスライブラリ

DESCryptoServiceProvider クラス

更新 : 2007 年 11 月

DES (Data Encryption Standard) アルゴリズムの暗号サービスプロバイダ (CSP : Cryptographic Service Provider) バージョンにアクセスする、ラッパーオブジェクトを定義します。このクラスは継承できません。

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 NotInheritable Class DESCryptoServiceProvider _
    Inherits DES

Visual Basic (使用法)

Dim instance As DESCryptoServiceProvider

[ComVisibleAttribute(true)]
public sealed class DESCryptoServiceProvider : DES

Visual C++

[ComVisibleAttribute(true)]
public ref class DESCryptoServiceProvider sealed : public DES

/** @attribute ComVisibleAttribute(true) */
public final class DESCryptoServiceProvider extends DES

JScript

public final class DESCryptoServiceProvider extends DES

解説

このアルゴリズムは、64 ビットのキー長をサポートしています。

例

次に示す例では、DESCryptoServiceProvider クラスを使用してデータを暗号化した後、そのデータを復号化します。

Visual Basic

' This sample demonstrates using a key based on the cryptographic service provider (CSP) version
' of the Data Encryption Standard (DES)algorithm to encrypt a string to a byte array, and then 
' to decrypt the byte array back to a string.
Imports System
Imports System.IO
Imports System.Text
Imports System.Security.Cryptography



Class CryptoMemoryStream

    ' Main method.
    Public Shared Sub Main()
        ' Create a new DES key.
        Dim key As New DESCryptoServiceProvider()

        ' Encrypt a string to a byte array.
        Dim buffer As Byte() = Encrypt("This is some plaintext!", key)

        ' Decrypt the byte array back to a string.
        Dim plaintext As String = Decrypt(buffer, key)

        ' Display the plaintext value to the console.
        Console.WriteLine(plaintext)
    End Sub 'Main


    ' Encrypt the string.
    Public Shared Function Encrypt(PlainText As String, key As SymmetricAlgorithm) As Byte()
        ' Create a memory stream.
        Dim ms As New MemoryStream()

        ' Create a CryptoStream using the memory stream and the 
        ' CSP DES key.  
        Dim encStream As New CryptoStream(ms, key.CreateEncryptor(), CryptoStreamMode.Write)

        ' Create a StreamWriter to write a string
        ' to the stream.
        Dim sw As New StreamWriter(encStream)

        ' Write the plaintext to the stream.
        sw.WriteLine(PlainText)

        ' Close the StreamWriter and CryptoStream.
        sw.Close()
        encStream.Close()

        ' Get an array of bytes that represents
        ' the memory stream.
        Dim buffer As Byte() = ms.ToArray()

        ' Close the memory stream.
        ms.Close()

        ' Return the encrypted byte array.
        Return buffer
    End Function 'Encrypt


    ' Decrypt the byte array.
    Public Shared Function Decrypt(CypherText() As Byte, key As SymmetricAlgorithm) As String
        ' Create a memory stream to the passed buffer.
        Dim ms As New MemoryStream(CypherText)

        ' Create a CryptoStream using the memory stream and the 
        ' CSP DES key. 
        Dim encStream As New CryptoStream(ms, key.CreateDecryptor(), CryptoStreamMode.Read)

        ' Create a StreamReader for reading the stream.
        Dim sr As New StreamReader(encStream)

        ' Read the stream as a string.
        Dim val As String = sr.ReadLine()

        ' Close the streams.
        sr.Close()
        encStream.Close()
        ms.Close()

        Return val
    End Function 'Decrypt
End Class 'CryptoMemoryStream

// This sample demonstrates using a key based on the cryptographic service provider (CSP) version
// of the Data Encryption Standard (DES)algorithm to encrypt a string to a byte array, and then 
// to decrypt the byte array back to a string.

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

class CryptoMemoryStream
{
    // Main method.
    public static void Main()
    {
        // Create a new DES key.
        DESCryptoServiceProvider key = new DESCryptoServiceProvider();

        // Encrypt a string to a byte array.
        byte[] buffer = Encrypt("This is some plaintext!", key);

        // Decrypt the byte array back to a string.
        string plaintext =  Decrypt(buffer, key);

        // Display the plaintext value to the console.
        Console.WriteLine(plaintext);
    }

    // Encrypt the string.
    public static byte[] Encrypt(string PlainText, SymmetricAlgorithm key)
    {
        // Create a memory stream.
        MemoryStream ms = new MemoryStream();

        // Create a CryptoStream using the memory stream and the 
        // CSP DES key.  
        CryptoStream encStream = new CryptoStream(ms, key.CreateEncryptor(), CryptoStreamMode.Write);

        // Create a StreamWriter to write a string
        // to the stream.
        StreamWriter sw = new StreamWriter(encStream);

        // Write the plaintext to the stream.
        sw.WriteLine(PlainText);

        // Close the StreamWriter and CryptoStream.
        sw.Close();
        encStream.Close();

        // Get an array of bytes that represents
        // the memory stream.
        byte[] buffer = ms.ToArray();

        // Close the memory stream.
        ms.Close();

        // Return the encrypted byte array.
        return buffer;
    }

   // Decrypt the byte array.
    public static string Decrypt(byte[] CypherText, SymmetricAlgorithm key)
    {
        // Create a memory stream to the passed buffer.
        MemoryStream ms = new MemoryStream(CypherText);

        // Create a CryptoStream using the memory stream and the 
        // CSP DES key. 
        CryptoStream encStream = new CryptoStream(ms, key.CreateDecryptor(), CryptoStreamMode.Read);

        // Create a StreamReader for reading the stream.
        StreamReader sr = new StreamReader(encStream);

        // Read the stream as a string.
        string val = sr.ReadLine();

        // Close the streams.
        sr.Close();
        encStream.Close();
        ms.Close();

        return val;
    }
}

Visual C++

// This sample demonstrates using a key based on the cryptographic service provider (CSP) version
// of the Data Encryption Standard (DES)algorithm to encrypt a string to a byte array, and then 
// to decrypt the byte array back to a string.
using namespace System;
using namespace System::IO;
using namespace System::Text;
using namespace System::Security::Cryptography;

// Encrypt the string.
array<Byte>^ Encrypt( String^ PlainText, SymmetricAlgorithm^ key )
{

   // Create a memory stream.
   MemoryStream^ ms = gcnew MemoryStream;

   // Create a CryptoStream using the memory stream and the 
   // CSP DES key.  
   CryptoStream^ encStream = gcnew CryptoStream( ms,key->CreateEncryptor(),CryptoStreamMode::Write );

   // Create a StreamWriter to write a string
   // to the stream.
   StreamWriter^ sw = gcnew StreamWriter( encStream );

   // Write the plaintext to the stream.
   sw->WriteLine( PlainText );

   // Close the StreamWriter and CryptoStream.
   sw->Close();
   encStream->Close();

   // Get an array of bytes that represents
   // the memory stream.
   array<Byte>^buffer = ms->ToArray();

   // Close the memory stream.
   ms->Close();

   // Return the encrypted byte array.
   return buffer;
}


// Decrypt the byte array.
String^ Decrypt( array<Byte>^CypherText, SymmetricAlgorithm^ key )
{

   // Create a memory stream to the passed buffer.
   MemoryStream^ ms = gcnew MemoryStream( CypherText );

   // Create a CryptoStream using the memory stream and the 
   // CSP DES key. 
   CryptoStream^ encStream = gcnew CryptoStream( ms,key->CreateDecryptor(),CryptoStreamMode::Read );

   // Create a StreamReader for reading the stream.
   StreamReader^ sr = gcnew StreamReader( encStream );

   // Read the stream as a string.
   String^ val = sr->ReadLine();

   // Close the streams.
   sr->Close();
   encStream->Close();
   ms->Close();
   return val;
}

int main()
{

   // Create a new DES key.
   DESCryptoServiceProvider^ key = gcnew DESCryptoServiceProvider;

   // Encrypt a string to a byte array.
   array<Byte>^buffer = Encrypt( "This is some plaintext!", key );

   // Decrypt the byte array back to a string.
   String^ plaintext = Decrypt( buffer, key );

   // Display the plaintext value to the console.
   Console::WriteLine( plaintext );
}

// This sample demonstrates using a key based on the cryptographic 
// service provider (CSP) version
// of the Data Encryption Standard (DES)algorithm to encrypt a string 
// to a byte array, and then to decrypt the byte array back to a string.

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

class CryptoMemoryStream
{
    // main method.
    public static void main(String[] args)
    {
        // Create a new DES key.
        DESCryptoServiceProvider key = new DESCryptoServiceProvider();

        // Encrypt a string to a byte array.
        ubyte buffer[] = Encrypt("This is some plaintext!", key);

        // Decrypt the byte array back to a string.
        String plainText = Decrypt(buffer, key);

        // Display the plaintext value to the console.
        Console.WriteLine(plainText);
    } //main

    // Encrypt the string.
    public static ubyte[] Encrypt(String plainText, SymmetricAlgorithm key)
    {
        // Create a memory stream.
        MemoryStream ms = new MemoryStream();

        // Create a CryptoStream using the memory stream and the 
        // CSP DES key.  
        CryptoStream encStream = new CryptoStream(ms, key.CreateEncryptor(), 
            CryptoStreamMode.Write);

        // Create a StreamWriter to write a string
        // to the stream.
        StreamWriter sw = new StreamWriter(encStream);

        // Write the plaintext to the stream.
        sw.WriteLine(plainText);

        // Close the StreamWriter and CryptoStream.
        sw.Close();
        encStream.Close();

        // Get an array of bytes that represents
        // the memory stream.
        ubyte buffer[] = ms.ToArray();

        // Close the memory stream.
        ms.Close();

        // Return the encrypted byte array.
        return buffer;
    } //Encrypt

    // Decrypt the byte array.
    public static String Decrypt(ubyte cypherText[], SymmetricAlgorithm key)
    {
        // Create a memory stream to the passed buffer.
        MemoryStream ms = new MemoryStream(cypherText);

        // Create a CryptoStream using the memory stream and the 
        // CSP DES key. 
        CryptoStream encStream = new CryptoStream(ms, key.CreateDecryptor(), 
            CryptoStreamMode.Read);

        // Create a StreamReader for reading the stream.
        StreamReader sr = new StreamReader(encStream);

        // Read the stream as a string.
        String val = sr.ReadLine();

        // Close the streams.
        sr.Close();
        encStream.Close();
        ms.Close();
        return val;
    } //Decrypt
} //CryptoMemoryStream

継承階層

System..::.Object
  System.Security.Cryptography..::.SymmetricAlgorithm
    System.Security.Cryptography..::.DES
      System.Security.Cryptography..::.DESCryptoServiceProvider

スレッドセーフ

この型のすべてのパブリック static (Visual Basic では Shared) メンバは、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。

プラットフォーム

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

.NET Framework および .NET Compact Framework では、各プラットフォームのすべてのバージョンはサポートしていません。サポートされているバージョンについては、「.NET Framework システム要件」を参照してください。

バージョン情報

.NET Framework

サポート対象 : 3.5、3.0、2.0、1.1、1.0

.NET Compact Framework

サポート対象 : 3.5、2.0

参照

DESCryptoServiceProvider メンバ

System.Security.Cryptography 名前空間

その他の技術情報

暗号サービス

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