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Check if an Email Was Received Digitally Signed

Demonstrates the read-only Chilkat Email.ReceivedSigned property, which is true if the email was originally received carrying one or more digital signatures. Knowing a message was signed is separate from knowing the signature checked out, so this example also reads SignaturesValid to report whether the signed content verified.

Background: A digital signature on an email (S/MIME) provides two things: authenticity (it was really sent by the holder of a particular certificate) and integrity (the content was not altered in transit). The sender signs a hash of the message with their private key; the recipient verifies it with the sender's public certificate. ReceivedSigned simply tells you a signature is present — verifying it is a separate step exposed through SignaturesValid.

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Local $bSuccess = False

;  Demonstrates the read-only Email.ReceivedSigned property, which is true if this
;  email was originally received with a digital signature.  Use SignaturesValid to
;  determine whether the signed content actually verified.

$oEmail = ObjCreate("Chilkat.Email")

$bSuccess = $oEmail.LoadEml("qa_data/eml/signed.eml")
If ($bSuccess = False) Then
    ConsoleWrite($oEmail.LastErrorText & @CRLF)
    Exit
EndIf

If ($oEmail.ReceivedSigned = True) Then
    ConsoleWrite("This email was received with a digital signature." & @CRLF)
    If ($oEmail.SignaturesValid = True) Then
        ConsoleWrite("All signatures are valid." & @CRLF)
    Else
        ConsoleWrite("One or more signatures are NOT valid." & @CRLF)
    EndIf

Else
    ConsoleWrite("This email was not signed." & @CRLF)
EndIf

;  Note: Paths such as "qa_data/..." are relative local filesystem paths,
;  relative to the current working directory of the running application.