Delphi ActiveX

Get an S/MIME Signing Time

Demonstrates the Chilkat Mime.GetSignatureSigningTimeStr method, which returns the CMS signingTime attribute for the signer at a zero-based index, as an RFC 822-style date string in GMT. The only argument is the signer index.

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: This is the timestamp the signer asserted at signing — useful for "when was this signed" audit trails and for evaluating whether the signing certificate was valid at that moment. Because it is a signed attribute, it is tamper-evident. Guard the call with HasSignatureSigningTime, since the attribute is optional. Note it is the signer's claim, not a trusted third-party timestamp.

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var
success: Integer;
mime: TChilkatMime;
n: Integer;
i: Integer;
signingTime: WideString;

begin
success := 0;

mime := TChilkatMime.Create(Self);
success := mime.LoadMimeFile('qa_data/signed.eml');
if (success = 0) then
  begin
    Memo1.Lines.Add(mime.LastErrorText);
    Exit;
  end;

//  After verifying, get the CMS signingTime for each signer that has one, as an RFC 822 date string
//  in GMT.  The only argument is the zero-based signer index.
success := mime.Verify();
if (success <> 1) then
  begin
    Memo1.Lines.Add(mime.LastErrorText);
    Exit;
  end;

n := mime.NumSignerCerts;

for i := 0 to n - 1 do
  begin
    //  Only signers that included a signing time have one to retrieve.
    if (mime.HasSignatureSigningTime(i)) then
      begin
        signingTime := mime.GetSignatureSigningTimeStr(i);
        if (mime.LastMethodSuccess = 0) then
          begin
            Memo1.Lines.Add(mime.LastErrorText);
            Exit;
          end;
        Memo1.Lines.Add('Signer ' + IntToStr(i) + ' signing time: ' + signingTime);
      end;
  end;