(Delphi DLL) Sign a Byte Array to Create an Opaque Signature in a Byte Array

Signs data contained in a byte array to produce an opaque signature (also in a byte array). An opaque signature is a PKCS7 signature (also known as CAdES) that embeds the signed data. Also shows how to verify the signature and extract the original data.

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

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, FileAccess, Cert, CkByteData, Crypt2;

...

procedure TForm1.Button1Click(Sender: TObject);
var
cert: HCkCert;
success: Boolean;
fac: HCkFileAccess;
fileBytes: HCkByteData;
crypt: HCkCrypt2;
sigBytes: HCkByteData;
originalData: HCkByteData;

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

cert := CkCert_Create();
success := CkCert_LoadPfxFile(cert,'qa_data/pfx/cert_test123.pfx','test123');
if (success = False) then
  begin
    Memo1.Lines.Add(CkCert__lastErrorText(cert));
    Exit;
  end;

fac := CkFileAccess_Create();

fileBytes := CkByteData_Create();
success := CkFileAccess_ReadEntireFile(fac,'qa_data/pdf/sample.pdf',fileBytes);
if (CkFileAccess_getLastMethodSuccess(fac) <> True) then
  begin
    Memo1.Lines.Add(CkFileAccess__lastErrorText(fac));
    Exit;
  end;

crypt := CkCrypt2_Create();

success := CkCrypt2_SetSigningCert(crypt,cert);

// We can sign any type of file.

sigBytes := CkByteData_Create();
success := CkCrypt2_OpaqueSignBytes(crypt,fileBytes,sigBytes);
if (CkCrypt2_getLastMethodSuccess(crypt) <> True) then
  begin
    Memo1.Lines.Add(CkCrypt2__lastErrorText(crypt));
    Exit;
  end;

success := CkFileAccess_WriteEntireFile(fac,'qa_output/sample.pdf.p7m',sigBytes);
if (CkFileAccess_getLastMethodSuccess(fac) <> True) then
  begin
    Memo1.Lines.Add(CkFileAccess__lastErrorText(fac));
    Exit;
  end;

// We can verify the opaque signature and extract the original data like this
originalData := CkByteData_Create();
success := CkCrypt2_OpaqueVerifyBytes(crypt,sigBytes,originalData);
if (CkCrypt2_getLastMethodSuccess(crypt) <> True) then
  begin
    Memo1.Lines.Add(CkCrypt2__lastErrorText(crypt));
    Exit;
  end;

success := CkFileAccess_WriteEntireFile(fac,'qa_output/sample.pdf',originalData);
if (CkFileAccess_getLastMethodSuccess(fac) <> True) then
  begin
    Memo1.Lines.Add(CkFileAccess__lastErrorText(fac));
    Exit;
  end;

Memo1.Lines.Add('Signature is verified and the original data was extracted.');

CkCert_Dispose(cert);
CkFileAccess_Dispose(fac);
CkByteData_Dispose(fileBytes);
CkCrypt2_Dispose(crypt);
CkByteData_Dispose(sigBytes);
CkByteData_Dispose(originalData);

end;