(Delphi ActiveX) Sign a Byte Array to Create a Detached Signature in a Byte Array

Signs data contained in a byte array to produce a detached signature (also in a byte array). Also shows how to verify the signature.

Chilkat for Delphi Downloads Chilkat ActiveX DLL for Delphi Chilkat non-ActiveX DLL for Delphi * The examples here use the ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Chilkat_TLB;

...

procedure TForm1.Button1Click(Sender: TObject);
var
cert: TChilkatCert;
success: Integer;
fac: TCkFileAccess;
fileBytes: Array of Byte;
crypt: TChilkatCrypt2;
sigBytes: Array of Byte;
verified: Integer;

begin
// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

cert := TChilkatCert.Create(Self);
success := cert.LoadPfxFile('qa_data/pfx/cert_test123.pfx','test123');
if (success = 0) then
  begin
    Memo1.Lines.Add(cert.LastErrorText);
    Exit;
  end;

fac := TCkFileAccess.Create(Self);

fileBytes := fac.ReadEntireFile('qa_data/pdf/sample.pdf');
if (fac.LastMethodSuccess <> 1) then
  begin
    Memo1.Lines.Add(fac.LastErrorText);
    Exit;
  end;

crypt := TChilkatCrypt2.Create(Self);

success := crypt.SetSigningCert(cert.ControlInterface);

// We can sign any type of file.
// The result is a detached signature (a signature that does not contain the data being signed).

sigBytes := crypt.SignBytes(fileBytes);
if (crypt.LastMethodSuccess <> 1) then
  begin
    Memo1.Lines.Add(crypt.LastErrorText);
    Exit;
  end;

success := fac.WriteEntireFile('qa_output/sample.pdf.p7s',sigBytes);
if (fac.LastMethodSuccess <> 1) then
  begin
    Memo1.Lines.Add(fac.LastErrorText);
    Exit;
  end;

// We can verify the detached signature like this
verified := crypt.VerifyBytes(fileBytes,sigBytes);
if (crypt.LastMethodSuccess <> 1) then
  begin
    Memo1.Lines.Add(crypt.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add('Verified = ' + IntToStr(Ord(verified)));
end;