(VB.NET) POP3 Verify Signed (S/MIME) Email

Demonstrates how to download and verify digitally signed S/MIME email.

Note: This example requires Chilkat v11.0.0 or greater.

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Dim success As Boolean = False

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

Dim mailman As New Chilkat.MailMan

' Set the POP3 server's hostname
mailman.MailHost = "pop.example.com"

' Set the POP3 login/password.
mailman.PopUsername = "myLogin"
mailman.PopPassword = "myPassword"

Dim stUidls As New Chilkat.StringTable
success = mailman.FetchUidls(stUidls)
If (success = False) Then
    Debug.WriteLine(mailman.LastErrorText)
    Exit Sub
End If


Dim email As New Chilkat.Email
Dim cert As New Chilkat.Cert

Dim count As Integer = stUidls.Count
Dim i As Integer = 0
While i < count
    ' Download the full email.
    success = mailman.FetchByUidl(stUidls.StringAt(i),False,0,email)
    If (success = False) Then
        Debug.WriteLine(mailman.LastErrorText)
        Exit Sub
    End If


    Debug.WriteLine(i)
    Debug.WriteLine("From: " & email.From)
    Debug.WriteLine("Subject: " & email.Subject)

    ' The security layers of signed and/or encrypted emails
    ' are automatically "unwrapped" when loaded into
    ' a Chilkat email object.
    ' An application only needs to check to see if an email
    ' was received signed or encrypted, and then examine
    ' the success/failure.  For example:
    If (email.ReceivedSigned = True) Then

        Debug.WriteLine("This email was signed.")

        ' Check to see if the signatures were verified.
        If (email.SignaturesValid = True) Then
            Debug.WriteLine("Digital signature(s) verified.")
            Debug.WriteLine("Signer: " & email.SignedBy)

            success = email.LastSignerCert(0,cert)
            If (success = False) Then
                Debug.WriteLine(email.LastErrorText)
                Exit Sub
            End If


            Debug.WriteLine("Signing cert: " & cert.SubjectCN)
        End If


    Else
        Debug.WriteLine("Digital signature verification failed.")
    End If


    i = i + 1
End While

mailman.Pop3EndSession()