Sign a File to Create a .p7s File (Detached Signature)

Delphi example to create a detached signature file (.p7s) for any type file. The signature can be verified by calling VerifyP7S and passing the original filename and the .p7s filename.

Download Chilkat Crypt ActiveX

uses
    Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
    Dialogs, StdCtrls,
    CHILKATCRYPT2Lib_TLB,
    CHILKATCERTIFICATELib_TLB,
    OleCtrls;

...

procedure TForm1.Button1Click(Sender: TObject);
var
crypt: TChilkatCrypt2;
success: Integer;
ccs: TChilkatCreateCS;
certStore: CHILKATCERTIFICATELib_TLB.IChilkatCertStore;
cert: CHILKATCRYPT2Lib_TLB.IChilkatCert;

begin
crypt := TChilkatCrypt2.Create(Self);

//  Any string argument automatically begins the 30-day trial.
success := crypt.UnlockComponent('30-day trial');
if (success <> 1) then
  begin
    ShowMessage('Crypt component unlock failed');
    Exit;
  end;

//  Find our digital certificate from the Current User certificate store.
ccs := TChilkatCreateCS.Create(Self);

certStore := ccs.OpenCurrentUserStore();

cert := certStore.FindCertBySubjectCN('Chilkat Software, Inc.') As CHILKATCRYPT2Lib_TLB.IChilkatCert;
if (cert = nil ) then
  begin
    ShowMessage(cert.LastErrorText);

    Exit;
  end;

//  Tell the crypt component to use this cert.
crypt.SetSigningCert(cert As CHILKATCRYPT2Lib_TLB.IChilkatCert);

//  We can sign any type of file, creating a .p7s as output:
success := crypt.CreateP7S('license.rtf','license.p7s');
if (success = 0) then
  begin
    ShowMessage(crypt.LastErrorText);

    Exit;
  end;

//  Verify the signature:
crypt.SetVerifyCert(cert As CHILKATCRYPT2Lib_TLB.IChilkatCert);

success := crypt.VerifyP7S('license.rtf','license.p7s');
if (success = 0) then
  begin
    ShowMessage(crypt.LastErrorText);

    Exit;
  end;

ShowMessage('Success!');
end;