(VB.NET) IMAP Download and Verify Signed (S/MIME) Email

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

Chilkat .NET Downloads Chilkat .NET Framework Chilkat for .NET Core

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


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


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


' We can choose to fetch UIDs or sequence numbers.
Dim fetchUids As Boolean = True

' Get the message IDs of all the emails in the mailbox
Dim messageSet As Chilkat.MessageSet = imap.Search("ALL",fetchUids)
If (imap.LastMethodSuccess <> True) Then
    Debug.WriteLine(imap.LastErrorText)
    Exit Sub
End If


' Scan for emails with attachments, and save the attachments
' to a sub-directory.
Dim i As Integer = 0
While i < messageSet.Count

    Dim uid As String = messageSet.GetId(i)
    Debug.WriteLine("uid: " & uid)

    Dim email As Chilkat.Email = imap.FetchSingle(uid,True)

    ' 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)

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

            End If


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


    End If




    i = i + 1
End While

' Disconnect from the IMAP server.
success = imap.Disconnect()