(Xojo Plugin) 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 Xojo Plugin Download Xojo Plugin for Windows, Linux, Mac OS X, and ARM, ARM64

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

Dim imap As New Chilkat.Imap

// Connect to an IMAP server.
// Use TLS
imap.Ssl = True
imap.Port = 993
Dim success As Boolean
success = imap.Connect("imap.someMailServer.com")
If (success <> True) Then
    System.DebugLog(imap.LastErrorText)
    Return
End If

success = imap.Login("myLogin","myPassword")
If (success <> True) Then
    System.DebugLog(imap.LastErrorText)
    Return
End If

// Select an IMAP mailbox
success = imap.SelectMailbox("Inbox")
If (success <> True) Then
    System.DebugLog(imap.LastErrorText)
    Return
End If

// Download the 1st email (as MIME) in the Inbox by sequence number.
Dim sbMime As New Chilkat.StringBuilder
success = imap.FetchSingleAsMimeSb(1,False,sbMime)
If (success <> True) Then
    System.DebugLog(imap.LastErrorText)
    Return
End If

// Load it into a MIME object and check to see if it is signed
Dim mime As New Chilkat.Mime
success = mime.LoadMimeSb(sbMime)
Dim alreadySavedParts As Boolean
alreadySavedParts = False
If (mime.ContainsSignedParts() = True) Then

    // This will save the .p7s and other parts...
    Dim sa As Chilkat.StringArray
    sa = mime.ExtractPartsToFiles("qa_output")
    If (mime.LastMethodSuccess = True) Then
        Dim numFiles As Int32
        numFiles = sa.Count
        Dim i As Int32
        i = 0
        While i < numFiles
            System.DebugLog("Created: " + sa.GetString(i))
            i = i + 1
        Wend

        alreadySavedParts = True
    End If

End If

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

If (email.ReceivedSigned = True) Then

    System.DebugLog("This email was signed.")

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

        System.DebugLog("Signer: " + email.SignedBy)

        // The certificate used for signing may be obtained
        // by calling email.GetSignedByCert.
        Dim cert As Chilkat.Cert
        cert = email.GetSignedByCert()
        If (email.LastMethodSuccess <> True) Then
            System.DebugLog("Failed to get signing certificate object.")
        Else
            System.DebugLog("Signing cert: " + cert.SubjectCN)

        End If

    End If

Else
    System.DebugLog("Digital signature verification failed.")
End If

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