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X509Chain Class

Represents a chain-building engine for X509Certificate2 certificates.

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

public class X509Chain
public class X509Chain
public class X509Chain
Not applicable.

The X509Chain object has a global error status called ChainStatus that should be used for certificate validation. The rules governing certificate validation are complex, and it is easy to oversimplify the validation logic by ignoring the error status of one or more of the elements involved. The global error status takes into consideration the status of each element in the chain.

The following code example opens the current user's personal certificate store, allows you to select a certificate, then writes certificate and certificate chain information to the console. The output depends on the certificate you select.

using System;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using System.IO;

class TestX509Chain
{
	static void Main(string[] args)
	{
		//Create new X509 store from local certificate store.
		X509Store store = new X509Store("MY", StoreLocation.CurrentUser);
		store.Open(OpenFlags.OpenExistingOnly | OpenFlags.ReadWrite);

		//Output store information.
		Console.WriteLine ("Store Information");
		Console.WriteLine ("Number of certificates in the store: {0}", store.Certificates.Count);
		Console.WriteLine ("Store location: {0}", store.Location);
		Console.WriteLine ("Store name: {0} {1}", store.Name, Environment.NewLine);
	
		//Put certificates from the store into a collection so user can select one.
		X509Certificate2Collection fcollection = (X509Certificate2Collection)store.Certificates;
		X509Certificate2Collection collection = X509Certificate2UI.SelectFromCollection(fcollection, "Select an X509 Certificate", "Choose a certificate to examine.", X509SelectionFlag.SingleSelection);
		X509Certificate2 certificate = collection[0];
		X509Certificate2UI.DisplayCertificate(certificate);
		//Output chain information of the selected certificate.
		X509Chain ch = new X509Chain();
		ch.Build (certificate);
		Console.WriteLine ("Chain Information");
		ch.ChainPolicy.RevocationMode = X509RevocationMode.Online;
		Console.WriteLine ("Chain revocation flag: {0}", ch.ChainPolicy.RevocationFlag);
		Console.WriteLine ("Chain revocation mode: {0}", ch.ChainPolicy.RevocationMode);
		Console.WriteLine ("Chain verification flag: {0}", ch.ChainPolicy.VerificationFlags);
		Console.WriteLine ("Chain verification time: {0}", ch.ChainPolicy.VerificationTime);
		Console.WriteLine ("Chain status length: {0}", ch.ChainStatus.Length);
		Console.WriteLine ("Chain application policy count: {0}", ch.ChainPolicy.ApplicationPolicy.Count);
		Console.WriteLine ("Chain certificate policy count: {0} {1}", ch.ChainPolicy.CertificatePolicy.Count, Environment.NewLine);
		//Output chain element information.
		Console.WriteLine ("Chain Element Information");
		Console.WriteLine ("Number of chain elements: {0}", ch.ChainElements.Count);
		Console.WriteLine ("Chain elements synchronized? {0} {1}", ch.ChainElements.IsSynchronized, Environment.NewLine);
	
		foreach (X509ChainElement element in ch.ChainElements)
		{
			Console.WriteLine ("Element issuer name: {0}", element.Certificate.Issuer);
			Console.WriteLine ("Element certificate valid until: {0}", element.Certificate.NotAfter);
			Console.WriteLine ("Element certificate is valid: {0}", element.Certificate.Verify ());
			Console.WriteLine ("Element error status length: {0}", element.ChainElementStatus.Length);
			Console.WriteLine ("Element information: {0}", element.Information);
			Console.WriteLine ("Number of element extensions: {0}{1}", element.Certificate.Extensions.Count, Environment.NewLine);

			if (ch.ChainStatus.Length > 1)
			{
				for (int index = 0; index < element.ChainElementStatus.Length; index++)
				{
					Console.WriteLine (element.ChainElementStatus[index].Status);
					Console.WriteLine (element.ChainElementStatus[index].StatusInformation);
				}
			}
		}
		store.Close();
	}
}

System.Object
  System.Security.Cryptography.X509Certificates.X509Chain

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 Server 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 Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0

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