X509Chain Class
Assembly: System (in system.dll)
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.
Imports System Imports System.Security.Cryptography Imports System.Security.Cryptography.X509Certificates Imports System.IO Class TestX509Chain Shared Sub Main(ByVal args() As String) 'Create new X509 store from local certificate store. Dim store As New X509Store("MY", StoreLocation.CurrentUser) store.Open(OpenFlags.OpenExistingOnly Or 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. Dim fcollection As X509Certificate2Collection = CType(store.Certificates, X509Certificate2Collection) Dim collection As X509Certificate2Collection = X509Certificate2UI.SelectFromCollection(fcollection, "Select an X509 Certificate", "Choose a certificate to examine.", X509SelectionFlag.SingleSelection) Dim certificate As X509Certificate2 = collection(0) X509Certificate2UI.DisplayCertificate(certificate) 'Output chain information of the selected certificate. Dim ch As 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) Dim element As X509ChainElement For Each 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 Then Dim index As Integer For index = 0 To element.ChainElementStatus.Length Console.WriteLine(element.ChainElementStatus(index).Status) Console.WriteLine(element.ChainElementStatus(index).StatusInformation) Next index End If Next element store.Close() End Sub End Class
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.