EnhancedKeyUsages Property
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X509EnhancedKeyUsageExtension.EnhancedKeyUsages Property

 

Gets the collection of object identifiers (OIDs) that indicate the applications that use the key.

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

public OidCollection EnhancedKeyUsages { get; }

Property Value

Type: System.Security.Cryptography.OidCollection

An OidCollection object indicating the applications that use the key.

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;
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.");
        }
    }
}

Universal Windows Platform
Available since 10
.NET Framework
Available since 2.0
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