Add S/MIME Signature using PFX

Add a digital signature to a MIME message using the certificate + private key from a PFX file.

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;
cert: TChilkatCert;
pfxFilepath: String;
pfxPassword: String;

begin
mime := CoChilkatMime.Create();

success := mime.UnlockComponent('Anything for 30-day trial');
if (success = 0) then
  begin
    Memo1.Lines.Add(mime.LastErrorText);
    Exit;
  end;

//  Load a PFX file into a certificate object.
cert := TChilkatCert.Create(Self);
pfxFilepath := 'pfxFiles/something.pfx';
pfxPassword := 'secret';
success := cert.LoadPfxFile(pfxFilepath,pfxPassword);
if (success = 0) then
  begin
    Memo1.Lines.Add(cert.LastErrorText);
    Exit;
  end;

mime.SetBodyFromPlainText('This is the plain-text MIME body.');

mime.Charset := 'utf-8';
mime.Encoding := 'quoted-printable';

//  Sign the MIME:
success := mime.AddDetachedSignature(cert.ControlInterface As CHILKATMIMELib_TLB.IChilkatCert);
if (success = 0) then
  begin
    Memo1.Lines.Add(mime.LastErrorText);
    Exit;
  end;

//  Save the S/MIME to a file.
success := mime.SaveMime('c:/temp/signedMime.txt');
if (success = 0) then
  begin
    Memo1.Lines.Add(mime.LastErrorText);
    Exit;
  end;

ShowMessage('success!');

end;