B4X Requires Chilkat v11.0.0+

IMAP Download and Verify Signed MIME

See more IMAP Examples

Downloads the original MIME of a digitally signed email and saves the .p7s signature along with other MIME parts. It then imports the email into a Chilkat email object to unwrap the S/MIME and verify the signature, and subsequently saves the attachments if they haven't been saved already. B4X

Dim success As Boolean = False

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

Dim imap As ChilkatImap
imap.Initialize("imap")

'  Connect to an IMAP server.
'  Use TLS
imap.Ssl = True
imap.Port = 993
success = imap.Connect("imap.example.com")
If success = False Then
    Log(imap.LastErrorText)
    Return
End If


success = imap.Login("myLogin", "myPassword")
If success = False Then
    Log(imap.LastErrorText)
    Return
End If


'  Select an IMAP mailbox
success = imap.SelectMailbox("Inbox")
If success = False Then
    Log(imap.LastErrorText)
    Return
End If


'  Download the 1st email (as MIME) in the Inbox by sequence number.
Dim sbMime As ChilkatStringBuilder
sbMime.Initialize
success = imap.FetchSingleAsMimeSb(1, False, sbMime)
If success = False Then
    Log(imap.LastErrorText)
    Return
End If


'  Load it into a MIME object and check to see if it is signed
Dim mime As ChilkatMime
mime.Initialize
mime.LoadMimeSb(sbMime)
Dim alreadySavedParts As Boolean = False
If mime.ContainsSignedParts = True Then

    '  This will save the .p7s and other parts...
    Dim st As ChilkatStringTable
    st.Initialize
    success = mime.PartsToFiles("c:/temp/qa_output", st)
    If success = True Then
        Dim numFiles As Int = st.Count
        Dim i As Int = 0
        Do While i < numFiles
            Log("Created: " & st.StringAt(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 ChilkatEmail
email.Initialize
email.SetFromMimeSb(sbMime)

If email.ReceivedSigned = True Then

    Log("This email was signed.")

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

        Log("Signer: " & email.SignedBy)

        '  The certificate used for signing may be obtained
        '  by calling email.GetSignedByCert.
        Dim cert As ChilkatCert
        cert.Initialize("cert")
        success = email.LastSignerCert(i, cert)
        If success = False Then
            Log("Failed to get signing certificate object.")
        Else
            Log("Signing cert: " & cert.SubjectCN)
        End If

    End If


Else
    Log("Digital signature verification failed.")
End If


If alreadySavedParts <> True Then
    email.SaveAllAttachments("c:/temp/qa_output")
End If