X509SubjectKeyIdentifierExtension クラス

.NET Framework クラス ライブラリ リファレンス

X509SubjectKeyIdentifierExtension クラス

メモ : このクラスは、.NET Framework version 2.0 で新しく追加されたものです。

証明書のサブジェクト キー識別子 (SKI: Subject Key Identifier) を示す文字列を定義します。このクラスは継承できません。

名前空間: System.Security.Cryptography.X509Certificates
アセンブリ: System (system.dll 内)
構文

Visual Basic (宣言)

Public NotInheritable Class
 X509SubjectKeyIdentifierExtension
    Inherits X509Extension

Visual Basic (使用法)

Dim instance As X509SubjectKeyIdentifierExtension

C#

public sealed class X509SubjectKeyIdentifierExtension
 : X509Extension

C++

public ref class X509SubjectKeyIdentifierExtension
 sealed : public X509Extension

J#

public final class X509SubjectKeyIdentifierExtension
 extends X509Extension

JScript

public final class X509SubjectKeyIdentifierExtension
 extends X509Extension

解説

証明書を識別する方法には、証明書のハッシュを使用する方法、発行者とシリアル番号を使用する方法、およびサブジェクト キー識別子 (SKI) を使用する方法があります。SKI を使用すると、証明書のサブジェクトを一意に識別できます。SKI は、XML デジタル署名を処理する場合によく使用されます。

使用例

ユーザーの個人用証明書ストアを開き、そこに格納されている各証明書に関する情報を表示するコード例を次に示します。この例では、X509SubjectKeyIdentifierExtension クラスを使用して情報を表示しています。

Visual Basic

Imports System
Imports System.Security.Cryptography
Imports System.Security.Cryptography.X509Certificates



Module CertSelect

    Sub Main()
        Try
            Dim store As New
 X509Store("MY", StoreLocation.CurrentUser)
            store.Open(OpenFlags.ReadOnly Or OpenFlags.OpenExistingOnly)

            Dim collection As X509Certificate2Collection
 = CType(store.Certificates, X509Certificate2Collection)
            Dim i As Integer
            For i = 0 To collection.Count
                Dim extension As X509Extension
                For Each extension In
 collection(i).Extensions
                    Console.WriteLine(extension.Oid.FriendlyName + "("
 + extension.Oid.Value + ")")


                    If extension.Oid.FriendlyName = "Key
 Usage" Then
                        Dim ext As X509KeyUsageExtension
 = CType(extension, X509KeyUsageExtension)
                        Console.WriteLine(ext.KeyUsages)
                    End If

                    If extension.Oid.FriendlyName = "Basic
 Constraints" Then
                        Dim ext As X509BasicConstraintsExtension
 = CType(extension, X509BasicConstraintsExtension)
                        Console.WriteLine(ext.CertificateAuthority)
                        Console.WriteLine(ext.HasPathLengthConstraint)
                        Console.WriteLine(ext.PathLengthConstraint)
                    End If

                    If extension.Oid.FriendlyName = "Subject
 Key Identifier" Then
                        Dim ext As X509SubjectKeyIdentifierExtension
 = CType(extension, X509SubjectKeyIdentifierExtension)
                        Console.WriteLine(ext.SubjectKeyIdentifier)
                    End If

                    If extension.Oid.FriendlyName = "Enhanced
 Key Usage" Then
                        Dim ext As X509EnhancedKeyUsageExtension
 = CType(extension, X509EnhancedKeyUsageExtension)
                        Dim oids As OidCollection
 = ext.EnhancedKeyUsages
                        Dim oid As Oid
                        For Each oid In
 oids
                            Console.WriteLine(oid.FriendlyName + "("
 + oid.Value + ")")
                        Next oid
                    End If
                Next extension
            Next i
            store.Close()
        Catch
            Console.WriteLine("Information could not be written
 out for this certificate.")
        End Try

    End Sub
End Module

C#

using System;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;

public class CertSelect
{
    public static void Main()
    {
        try
        {
            X509Store store = new X509Store("MY", StoreLocation.CurrentUser);
            store.Open(OpenFlags.ReadOnly | OpenFlags.OpenExistingOnly);

            X509Certificate2Collection collection = (X509Certificate2Collection)store.Certificates;
            for (int i = 0; i < collection.Count;
 i++)
            {
                foreach (X509Extension extension in
 collection[i].Extensions)
                {
                    Console.WriteLine(extension.Oid.FriendlyName + "("
 + extension.Oid.Value + ")");
   

                    if (extension.Oid.FriendlyName == "Key
 Usage")
                    {
                        X509KeyUsageExtension ext = (X509KeyUsageExtension)extension;
                        Console.WriteLine(ext.KeyUsages);
                    }

                    if (extension.Oid.FriendlyName == "Basic
 Constraints")
                    {
                        X509BasicConstraintsExtension ext = (X509BasicConstraintsExtension)extension;
                        Console.WriteLine(ext.CertificateAuthority);
                        Console.WriteLine(ext.HasPathLengthConstraint);
                        Console.WriteLine(ext.PathLengthConstraint);
                    }

                    if (extension.Oid.FriendlyName == "Subject
 Key Identifier")
                    {
                        X509SubjectKeyIdentifierExtension ext = (X509SubjectKeyIdentifierExtension)extension;
                        Console.WriteLine(ext.SubjectKeyIdentifier);
                    }

                    if (extension.Oid.FriendlyName == "Enhanced
 Key Usage")
                    {
                        X509EnhancedKeyUsageExtension ext = (X509EnhancedKeyUsageExtension)extension;
                        OidCollection oids = ext.EnhancedKeyUsages;
                        foreach (Oid oid in
 oids)
                        {
                            Console.WriteLine(oid.FriendlyName + "(" +
 oid.Value + ")");
                        }
                    }
                }
            }
            store.Close();
        }
        catch (CryptographicException)
        {
            Console.WriteLine("Information could not be written out for
 this certificate.");
        }
    }
}

C++

#using <System.dll>
#using <system.security.dll>

using namespace System;
using namespace System::Security::Cryptography;
using namespace System::Security::Cryptography::X509Certificates;
int main()
{
   try
   {
      X509Store^ store = gcnew X509Store( L"MY",StoreLocation::CurrentUser
 );
      store->Open( static_cast<OpenFlags>(OpenFlags::ReadOnly | OpenFlags::OpenExistingOnly)
 );
      X509Certificate2Collection^ collection = dynamic_cast<X509Certificate2Collection^>(store->Certificates);
      for ( int i = 0; i < collection->Count;
 i++ )
      {
         System::Collections::IEnumerator^ myEnum = collection[ i ]->Extensions->GetEnumerator();
         while ( myEnum->MoveNext() )
         {
            X509Extension^ extension = safe_cast<X509Extension^>(myEnum->Current);
            Console::WriteLine( L"{0}({1})", extension->Oid->FriendlyName,
 extension->Oid->Value );
            if ( extension->Oid->FriendlyName == L"Key
 Usage" )
            {
               X509KeyUsageExtension^ ext = dynamic_cast<X509KeyUsageExtension^>(extension);
               Console::WriteLine( ext->KeyUsages );
            }
            if ( extension->Oid->FriendlyName == L"Basic
 Constraints" )
            {
               X509BasicConstraintsExtension^ ext = dynamic_cast<X509BasicConstraintsExtension^>(extension);
               Console::WriteLine( ext->CertificateAuthority );
               Console::WriteLine( ext->HasPathLengthConstraint );
               Console::WriteLine( ext->PathLengthConstraint );
            }
            if ( extension->Oid->FriendlyName == L"Subject
 Key Identifier" )
            {
               X509SubjectKeyIdentifierExtension^ ext = dynamic_cast<X509SubjectKeyIdentifierExtension^>(extension);
               Console::WriteLine( ext->SubjectKeyIdentifier );
            }
            if ( extension->Oid->FriendlyName == L"Enhanced
 Key Usage" )
            {
               X509EnhancedKeyUsageExtension^ ext = dynamic_cast<X509EnhancedKeyUsageExtension^>(extension);
               OidCollection^ oids = ext->EnhancedKeyUsages;
               System::Collections::IEnumerator^ myEnum1 = oids->GetEnumerator();
               while ( myEnum1->MoveNext() )
               {
                  Oid^ oid = safe_cast<Oid^>(myEnum1->Current);
                  Console::WriteLine( L"{0}({1})", oid->FriendlyName,
 oid->Value );
               }
            }
         }

      }
      store->Close();
   }
   catch ( CryptographicException^ ) 
   {
      Console::WriteLine( L"Information could not be written out for
 this certificate." );
   }

}

継承階層

System.Object
   System.Security.Cryptography.AsnEncodedData
     System.Security.Cryptography.X509Certificates.X509Extension
      System.Security.Cryptography.X509Certificates.X509SubjectKeyIdentifierExtension

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 Millennium Edition, 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

参照

関連項目
X509SubjectKeyIdentifierExtension メンバ
System.Security.Cryptography.X509Certificates 名前空間