Classic ASP

Check for an S/MIME Signing Time

Demonstrates the Chilkat Mime.HasSignatureSigningTime method, which returns whether the signer at a zero-based index included a CMS signingTime signed attribute. The only argument is the signer index; use NumSignerCerts for the count.

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 signing time records when the signer claims to have signed, which matters for auditing and for validating a certificate that has since expired. It is an optional signed attribute, so not every signature has one — this predicate lets you check before calling GetSignatureSigningTimeStr, avoiding an error for signers that omitted it. Being a signed attribute, it is covered by the signature and cannot be altered undetected.

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

'  After verifying, check whether each signer included a CMS signingTime signed attribute.  The
'  only argument is the zero-based signer index.
success = mime.Verify()
If (success <> 1) Then
    Response.Write "<pre>" & Server.HTMLEncode( mime.LastErrorText) & "</pre>"
    Response.End
End If

n = mime.NumSignerCerts

For i = 0 To n - 1
    If (mime.HasSignatureSigningTime(i)) Then
        Response.Write "<pre>" & Server.HTMLEncode( "Signer " & i & " included a signing time.") & "</pre>"
    Else
        Response.Write "<pre>" & Server.HTMLEncode( "Signer " & i & " did not include a signing time.") & "</pre>"
    End If

Next

%>
</body>
</html>