X509KeyUsageExtension Constructors

Definition

Namespace:

System.Security.Cryptography.X509Certificates

Assembly:

System.Security.Cryptography.dll

Initializes a new instance of the X509KeyUsageExtension class.

Overloads

X509KeyUsageExtension()	Initializes a new instance of the X509KeyUsageExtension class.
X509KeyUsageExtension(AsnEncodedData, Boolean)	Initializes a new instance of the X509KeyUsageExtension class using an AsnEncodedData object and a value that identifies whether the extension is critical.
X509KeyUsageExtension(X509KeyUsageFlags, Boolean)	Initializes a new instance of the X509KeyUsageExtension class using the specified X509KeyUsageFlags value and a value that identifies whether the extension is critical.

X509KeyUsageExtension()

Source:

X509KeyUsageExtension.cs

Initializes a new instance of the X509KeyUsageExtension class.

public:
 X509KeyUsageExtension();

public X509KeyUsageExtension ();

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 X509KeyUsageExtension 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

X509KeyUsageExtension(AsnEncodedData, Boolean)

Source:

X509KeyUsageExtension.cs

Initializes a new instance of the X509KeyUsageExtension class using an AsnEncodedData object and a value that identifies whether the extension is critical.

public:
 X509KeyUsageExtension(System::Security::Cryptography::AsnEncodedData ^ encodedKeyUsage, bool critical);

public X509KeyUsageExtension (System.Security.Cryptography.AsnEncodedData encodedKeyUsage, bool critical);

new System.Security.Cryptography.X509Certificates.X509KeyUsageExtension : System.Security.Cryptography.AsnEncodedData * bool -> System.Security.Cryptography.X509Certificates.X509KeyUsageExtension

Public Sub New (encodedKeyUsage As AsnEncodedData, critical As Boolean)

Parameters

encodedKeyUsage

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.

X509KeyUsageExtension(X509KeyUsageFlags, Boolean)

Source:

X509KeyUsageExtension.cs

Initializes a new instance of the X509KeyUsageExtension class using the specified X509KeyUsageFlags value and a value that identifies whether the extension is critical.

public:
 X509KeyUsageExtension(System::Security::Cryptography::X509Certificates::X509KeyUsageFlags keyUsages, bool critical);

public X509KeyUsageExtension (System.Security.Cryptography.X509Certificates.X509KeyUsageFlags keyUsages, bool critical);

new System.Security.Cryptography.X509Certificates.X509KeyUsageExtension : System.Security.Cryptography.X509Certificates.X509KeyUsageFlags * bool -> System.Security.Cryptography.X509Certificates.X509KeyUsageExtension

Public Sub New (keyUsages As X509KeyUsageFlags, critical As Boolean)

Parameters

keyUsages

X509KeyUsageFlags

One of the X509KeyUsageFlags values that describes how to use the key.

critical

Boolean

true if the extension is critical; otherwise, false.