DESCryptoServiceProvider クラス

.NET Framework クラス ライブラリ リファレンス

DESCryptoServiceProvider クラス

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

C#

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

C++

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

J#

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

JScript

ComVisibleAttribute(true) 
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。

使用例

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

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 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;
    }
}

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 );
}

J#

// 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 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。

プラットフォーム

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

開発プラットフォームの中には、.NET Framework によってサポートされていないバージョンがあります。サポートされているバージョンについては、「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 : 2.0、1.1、1.0
.NET Compact Framework
サポート対象 : 2.0

参照

関連項目
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