Create S/MIME Detached Signature with PFX

How to use a PFX to create a signed S/MIME message.

Download Chilkat MIME ActiveX

uses
    Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
    Dialogs, StdCtrls,
    CHILKATMIMELib_TLB,
    CHILKATCERTIFICATELib_TLB,
    OleCtrls;

...

procedure TForm1.Button1Click(Sender: TObject);
var
mime: CHILKATMIMELib_TLB.IChilkatMime;
success: Integer;
certStore: CHILKATCERTIFICATELib_TLB.IChilkatCertStore;
password: String;
cert: CHILKATMIMELib_TLB.IChilkatCert;

begin
mime := CoChilkatMime.Create();

success := mime.UnlockComponent('Anything for 30-day trial');
if (success = 0) then
  begin
    ShowMessage('Failed to unlock component');
    Exit;
  end;

mime.AddHeaderField('Subject','This is a test');
mime.AddHeaderField('Abc','123');

mime.SetBodyFromPlainText('This is the body');

certStore := CoChilkatCertStore.Create();

password := 'myPassword';
success := certStore.LoadPfxFile('chilkat.pfx',password);
if (success = 0) then
  begin
    ShowMessage(certStore.LastErrorText);
    Exit;
  end;

cert := certStore.FindCertBySubjectCN('Chilkat Software, Inc.') As CHILKATMIMELib_TLB.IChilkatCert;
if (cert = nil ) then
  begin
    ShowMessage('Failed to find certificate!');
    Exit;
  end;

//  Display the full distinguished name of the cert.
Memo1.Lines.Add(cert.SubjectDN);

success := mime.AddDetachedSignature(cert As CHILKATMIMELib_TLB.IChilkatCert);
if (success = 0) then
  begin
    ShowMessage(mime.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add(mime.GetMime());
end;