(Excel) 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).

Download Excel Class Modules Chilkat Excel Class Modules

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

Dim imap As Chilkat.Imap
Set imap = Chilkat.NewImap

' Connect to an IMAP server.
' Use TLS
imap.Ssl = True
imap.Port = 993

success = imap.Connect("imap.someMailServer.com")
If (success <> True) Then
    Debug.Print imap.LastErrorText
    Exit Sub
End If

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

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

' Download the 1st email (as MIME) in the Inbox by sequence number.
Dim sbMime As Chilkat.StringBuilder
Set sbMime = Chilkat.NewStringBuilder
success = imap.FetchSingleAsMimeSb(1,False,sbMime)
If (success <> True) 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 Chilkat.Mime
Set mime = Chilkat.NewMime
success = mime.LoadMimeSb(sbMime)

alreadySavedParts = False
If (mime.ContainsSignedParts() = True) Then

    ' This will save the .p7s and other parts...

    Set sa = mime.ExtractPartsToFiles("qa_output")
    If (mime.LastMethodSuccess = True) Then

        numFiles = sa.Count

        i = 0
        Do While i < numFiles
            Debug.Print "Created: "; sa.GetString(i)
            i = i + 1
        Loop

        alreadySavedParts = True
    End If

End If

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

If (email.ReceivedSigned = True) Then

    Debug.Print "This email was signed."

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

        Debug.Print "Signer: "; email.SignedBy

        ' The certificate used for signing may be obtained
        ' by calling email.GetSignedByCert.

        Set cert = email.GetSignedByCert()
        If (email.LastMethodSuccess <> True) 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 <> True) Then
    success = email.SaveAllAttachments("qa_output")
End If