Sign a File to Create a .p7s (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;
signingCertSubject: String;
pfxFilename: String;
pfxPassword: String;
certStore: CHILKATCERTIFICATELib_TLB.IChilkatCertStore;
cert: CHILKATCRYPT2Lib_TLB.IChilkatCert;
inFile: String;
sigFile: String;

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
    Memo1.Lines.Add(crypt.LastErrorText);
    Exit;
  end;

//  Use a digital certificate and private key from a PFX file (.pfx or .p12).
signingCertSubject := 'Acme Inc';
pfxFilename := '/Users/chilkat/testData/pfx/acme.pfx';
pfxPassword := 'test123';

certStore := CoChilkatCertStore.Create();
success := certStore.LoadPfxFile(pfxFilename,pfxPassword);
if (success <> 1) then
  begin
    Memo1.Lines.Add(certStore.LastErrorText);
    Exit;
  end;

cert := certStore.FindCertBySubjectCN(signingCertSubject) As CHILKATCRYPT2Lib_TLB.IChilkatCert;
if (cert = nil ) then
  begin
    Memo1.Lines.Add('Failed to find certificate by subject common name.');
    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:
inFile := '/Users/chilkat/testData/pdf/sample.pdf';
sigFile := '/Users/chilkat/testData/p7s/sample.p7s';

success := crypt.CreateP7S(inFile,sigFile);
if (success = 0) then
  begin
    Memo1.Lines.Add(crypt.LastErrorText);

    Exit;
  end;

success := crypt.VerifyP7S(inFile,sigFile);
if (success = 0) then
  begin
    Memo1.Lines.Add(crypt.LastErrorText);

    Exit;
  end;

ShowMessage('Success!');
end;