(VB.NET) Examine SSL/TLS Server Certificate

See more Socket/SSL/TLS Examples

Demonstrates how an application can examine and check a server's SSL/TLS certificate.

Chilkat .NET Downloads Chilkat .NET Framework Chilkat for .NET Core

' This example assumes the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.

Dim socket As New Chilkat.Socket

' Connect to a server.
Dim useTls As Boolean = True
Dim maxWaitMs As Integer = 2000
Dim success As Boolean = socket.Connect("www.intel.com",443,useTls,maxWaitMs)
If (success = False) Then
    Debug.WriteLine(socket.LastErrorText)
    Exit Sub
End If


' If we get here, the TLS connection ws made..
' In any SSL/TLS handshake, the server sends its certificate in a TLS handshake message.
' Chilkat will keep it cached within the object that made the connection.
' Get the server's cert and examine a few things.
Dim cert As Chilkat.Cert = socket.GetSslServerCert()
If (socket.LastMethodSuccess = False) Then
    ' This is unexpected..
    Debug.WriteLine(socket.LastErrorText)
    Exit Sub
End If


Debug.WriteLine("Distinguished Name: " & cert.SubjectDN)
Debug.WriteLine("Common Name: " & cert.SubjectCN)
Debug.WriteLine("Issuer Distinguished Name: " & cert.IssuerDN)
Debug.WriteLine("Issuer Common Name: " & cert.IssuerCN)

Debug.WriteLine("Expired: " & cert.Expired)
Debug.WriteLine("Revoked: " & cert.Revoked)
Debug.WriteLine("Signature Verified: " & cert.SignatureVerified)
Debug.WriteLine("Trusted Root: " & cert.TrustedRoot)

' Sample output:

' Distinguished Name: C=US, ST=California, O=Intel Corporation, CN=*.intel.com
' Common Name: *.intel.com
' Issuer Distinguished Name: C=GB, ST=Greater Manchester, L=Salford, O=Sectigo Limited, CN=Sectigo RSA Organization Validation Secure Server CA
' Issuer Common Name: Sectigo RSA Organization Validation Secure Server CA
' Expired: False
' Revoked: False
' Signature Verified: True
' Trusted Root: True