Classic ASP

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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Classic ASP

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body>
<%
success = 0

set mime = Server.CreateObject("Chilkat.Mime")
success = mime.SetBodyFromPlainText("This message will be signed.")
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( mime.LastErrorText) & "</pre>"
    Response.End
End If

'  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.
pfxPassword = "myPfxPassword"
set cert = Server.CreateObject("Chilkat.Cert")
success = cert.LoadPfxFile("qa_data/signer.pfx",pfxPassword)
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( cert.LastErrorText) & "</pre>"
    Response.End
End If

'  Create an S/MIME detached signature.  The object becomes a multipart/signed entity with the
'  original content and a separate signature part.
success = mime.AddDetachedSignature(cert)
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( mime.LastErrorText) & "</pre>"
    Response.End
End If

success = mime.SaveMime("qa_output/signed.eml")
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( mime.LastErrorText) & "</pre>"
    Response.End
End If

Response.Write "<pre>" & Server.HTMLEncode( "Detached signature added.") & "</pre>"

%>
</body>
</html>