X509KeyUsageExtension Class

Note: This class is new in the .NET Framework version 2.0.

Defines the usage of a key contained within an X.509 certificate. This class cannot be inherited.

Namespace: System.Security.Cryptography.X509Certificates
Assembly: System (in system.dll)

public sealed class X509KeyUsageExtension : X509Extension
public final class X509KeyUsageExtension extends X509Extension
public final class X509KeyUsageExtension extends X509Extension

The X509KeyUsageExtension class uses the flags in the X509KeyUsageFlags enumeration to define or determine key usage.

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.


Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0

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