(Visual Basic 6.0) IMAP Download and Verify Signed MIME

Downloads the unmodified MIME of a digitally signed email, saves the .p7s signature (and other MIME parts), then loads the email into a Chilkat email object (which unwraps the S/MIME and verifies the signature) and then saves attachments (if the MIME parts were not already saved).

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

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

Dim imap As New ChilkatImap

' Connect to an IMAP server.
' Use TLS
imap.Ssl = 1
imap.Port = 993
Dim success As Long
success = imap.Connect("imap.someMailServer.com")
If (success <> 1) Then
    Debug.Print imap.LastErrorText
    Exit Sub
End If

success = imap.Login("myLogin","myPassword")
If (success <> 1) Then
    Debug.Print imap.LastErrorText
    Exit Sub
End If

' Select an IMAP mailbox
success = imap.SelectMailbox("Inbox")
If (success <> 1) Then
    Debug.Print imap.LastErrorText
    Exit Sub
End If

' Download the 1st email (as MIME) in the Inbox by sequence number.
Dim sbMime As New ChilkatStringBuilder
success = imap.FetchSingleAsMimeSb(1,0,sbMime)
If (success <> 1) Then
    Debug.Print imap.LastErrorText
    Exit Sub
End If

' Load it into a MIME object and check to see if it is signed
Dim mime As New ChilkatMime
success = mime.LoadMimeSb(sbMime)
Dim alreadySavedParts As Long
alreadySavedParts = 0
If (mime.ContainsSignedParts() = 1) Then

    ' This will save the .p7s and other parts...
    Dim sa As CkStringArray
    Set sa = mime.ExtractPartsToFiles("qa_output")
    If (mime.LastMethodSuccess = 1) Then
        Dim numFiles As Long
        numFiles = sa.Count
        Dim i As Long
        i = 0
        Do While i < numFiles
            Debug.Print "Created: " & sa.GetString(i)
            i = i + 1
        Loop

        alreadySavedParts = 1
    End If

End If

' Load the MIME into an Email object.  This unwraps the security layers and verifies signatures.
Dim email As New ChilkatEmail
success = email.SetFromMimeSb(sbMime)

If (email.ReceivedSigned = 1) Then

    Debug.Print "This email was signed."

    ' Check to see if the signatures were verified.
    If (email.SignaturesValid = 1) Then
        Debug.Print "Digital signature(s) verified."

        Debug.Print "Signer: " & email.SignedBy

        ' The certificate used for signing may be obtained
        ' by calling email.GetSignedByCert.
        Dim cert As ChilkatCert
        Set cert = email.GetSignedByCert()
        If (email.LastMethodSuccess <> 1) Then
            Debug.Print "Failed to get signing certificate object."
        Else
            Debug.Print "Signing cert: " & cert.SubjectCN

        End If

    End If

Else
    Debug.Print "Digital signature verification failed."
End If

If (alreadySavedParts <> 1) Then
    success = email.SaveAllAttachments("qa_output")
End If