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Add an S/MIME Detached Signature

Demonstrates the Chilkat Mime.AddDetachedSignature method, which creates an S/MIME detached signature. The only argument is the signing Cert, which must have access to its private key. On success the entity becomes a multipart/signed with the content and a separate signature part.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: A detached signature (multipart/signed) keeps the original content readable alongside a separate signature part — so recipients whose software does not understand S/MIME still see the message, they just cannot verify it. That backward compatibility makes detached the usual choice for signed email. The signer proves authorship with a certificate that carries its private key.

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Local $bSuccess = False

$oMime = ObjCreate("Chilkat.Mime")
$bSuccess = $oMime.SetBodyFromPlainText("This message will be signed.")
If ($bSuccess = False) Then
    ConsoleWrite($oMime.LastErrorText & @CRLF)
    Exit
EndIf

;  Load the signing certificate (which must have access to its private key) from a PFX file.
;  The PFX password should come from a secure source rather than being hard-coded.
Local $sPfxPassword = "myPfxPassword"
$oCert = ObjCreate("Chilkat.Cert")
$bSuccess = $oCert.LoadPfxFile("qa_data/signer.pfx",$sPfxPassword)
If ($bSuccess = False) Then
    ConsoleWrite($oCert.LastErrorText & @CRLF)
    Exit
EndIf

;  Create an S/MIME detached signature.  The object becomes a multipart/signed entity with the
;  original content and a separate signature part.
$bSuccess = $oMime.AddDetachedSignature($oCert)
If ($bSuccess = False) Then
    ConsoleWrite($oMime.LastErrorText & @CRLF)
    Exit
EndIf

$bSuccess = $oMime.SaveMime("qa_output/signed.eml")
If ($bSuccess = False) Then
    ConsoleWrite($oMime.LastErrorText & @CRLF)
    Exit
EndIf

ConsoleWrite("Detached signature added." & @CRLF)