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X509Chain Class

Represents a chain-building engine for X509Certificate2 certificates.

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

'Declaration
Public Class X509Chain
'Usage
Dim instance As X509Chain

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

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 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

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

.NET Framework

Supported in: 3.5, 3.0, 2.0
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