X509EnhancedKeyUsageExtension Constructors
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
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;
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.
Applies to
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.X509EnhancedKeyUsageExtensionPublic 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.
Applies to
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.X509EnhancedKeyUsageExtensionPublic 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.
