B4X

Get the Server Certificate from a TLS Connection

Demonstrates Socket.GetServerCert, which copies the certificate presented by the remote TLS server into a Cert object for inspection.

Background. The method returns false when the socket is not connected, is not using TLS, or no server certificate is available. Inspecting the certificate lets an application validate the server's identity.

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B4X

Dim success As Boolean = False

Dim socket As ChilkatSocket
socket.Initialize("socket")

'  Connect to the server using TLS.
Dim bTls As Boolean = True
Dim maxWaitMs As Int = 5000
success = socket.Connect("example.com", 5000, bTls, maxWaitMs)
If success = False Then
    Log(socket.LastErrorText)
    Return
End If


'  Copy the certificate presented by the remote TLS server, then inspect it.  This can be used to
'  validate the server's identity.
Dim cert As ChilkatCert
cert.Initialize("cert")
success = socket.GetServerCert(cert)
If success = False Then
    Log(socket.LastErrorText)
    Return
End If

Log("Server certificate subject: " & cert.SubjectCN)
Log("Issued by: " & cert.IssuerCN)