X509EnhancedKeyUsageExtension Constructors

Definition

Initializes a new instance of the X509EnhancedKeyUsageExtension class.

Overloads

X509EnhancedKeyUsageExtension()

Initializes a new instance of the X509EnhancedKeyUsageExtension class.

X509EnhancedKeyUsageExtension(AsnEncodedData, Boolean)

Initializes a new instance of the X509EnhancedKeyUsageExtension class using an AsnEncodedData object and a value that identifies whether the extension is critical.

X509EnhancedKeyUsageExtension(OidCollection, Boolean)

Initializes a new instance of the X509EnhancedKeyUsageExtension class using an OidCollection and a value that identifies whether the extension is critical.

X509EnhancedKeyUsageExtension()

Initializes a new instance of the X509EnhancedKeyUsageExtension class.

public:
 X509EnhancedKeyUsageExtension();
public X509EnhancedKeyUsageExtension ();
Public Sub New ()

Examples

The following code example demonstrates how to open a user's personal certificate store and display information about each certificate in the store. This example uses the X509EnhancedKeyUsageExtension class to display the information.

#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." );
   }

}

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.");
        }
    }
}
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)
            For i As Integer = 0 To collection.Count - 1
                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

Remarks

Use this method to create a new instance of the X509EnhancedKeyUsageExtension class. After the instance has been created, you can then use the EnhancedKeyUsages property to obtain the collection of object identifiers (OIDs) that indicate the applications that use the key.

X509EnhancedKeyUsageExtension(AsnEncodedData, Boolean)

Initializes a new instance of the X509EnhancedKeyUsageExtension class using an AsnEncodedData object and a value that identifies whether the extension is critical.

public:
 X509EnhancedKeyUsageExtension(System::Security::Cryptography::AsnEncodedData ^ encodedEnhancedKeyUsages, bool critical);
public X509EnhancedKeyUsageExtension (System.Security.Cryptography.AsnEncodedData encodedEnhancedKeyUsages, bool critical);
new System.Security.Cryptography.X509Certificates.X509EnhancedKeyUsageExtension : System.Security.Cryptography.AsnEncodedData * bool -> System.Security.Cryptography.X509Certificates.X509EnhancedKeyUsageExtension
Public Sub New (encodedEnhancedKeyUsages As AsnEncodedData, critical As Boolean)

Parameters

encodedEnhancedKeyUsages
AsnEncodedData

The encoded data to use to create the extension.

critical
Boolean

true if the extension is critical; otherwise, false.

Remarks

Use this constructor if the information to create the extension is already in an AsnEncodedData object.

X509EnhancedKeyUsageExtension(OidCollection, Boolean)

Initializes a new instance of the X509EnhancedKeyUsageExtension class using an OidCollection and a value that identifies whether the extension is critical.

public:
 X509EnhancedKeyUsageExtension(System::Security::Cryptography::OidCollection ^ enhancedKeyUsages, bool critical);
public X509EnhancedKeyUsageExtension (System.Security.Cryptography.OidCollection enhancedKeyUsages, bool critical);
new System.Security.Cryptography.X509Certificates.X509EnhancedKeyUsageExtension : System.Security.Cryptography.OidCollection * bool -> System.Security.Cryptography.X509Certificates.X509EnhancedKeyUsageExtension
Public Sub New (enhancedKeyUsages As OidCollection, critical As Boolean)

Parameters

enhancedKeyUsages
OidCollection

An OidCollection collection.

critical
Boolean

true if the extension is critical; otherwise, false.

Exceptions

The specified OidCollection contains one or more corrupt values.

Applies to