Delphi DLL Requires Chilkat v11.7.0+

Encrypt a PDF for a Certificate Instead of a Password

See more PDF Protection Examples

Demonstrates certificate security, where a PDF is encrypted for one or more recipients and each opens it with their own certificate and private key. No password is involved. Only the public certificate of a recipient is needed to encrypt. Each recipient has its own permissions, and the changeSecurity permission gives a recipient owner rights. PreLoadCheck tells an application that a file is certificate-encrypted and which certificates can open it. A PDF that cannot be opened, because no matching certificate and private key were provided, fails to load. Delphi DLL

var
success: Boolean;
recipient: HCkCert;
pdf: HCkPdf;
json: HCkJsonObject;
jsonOut: HCkJsonObject;
reader: HCkPdf;
info: HCkJsonObject;
myCert: HCkCert;
empty: HCkJsonObject;
loadedInfo: HCkJsonObject;

begin
success := False;

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

//  The PDF used in this example is available at two_page_memo.pdf

//  The recipient's certificate.  Only the public certificate is needed to encrypt.
recipient := CkCert_Create();
success := CkCert_LoadFromFile(recipient,'qa_data/certs/recipient.cer');
if (success = False) then
  begin
    Memo1.Lines.Add(CkCert__lastErrorText(recipient));
    Exit;
  end;

pdf := CkPdf_Create();
success := CkPdf_LoadFile(pdf,'qa_data/pdf/two_page_memo.pdf');
if (success = False) then
  begin
    Memo1.Lines.Add(CkPdf__lastErrorText(pdf));
    Exit;
  end;

//  Call AddEncryptCert once for each recipient.
success := CkPdf_AddEncryptCert(pdf,recipient);
if (success = False) then
  begin
    Memo1.Lines.Add(CkPdf__lastErrorText(pdf));
    Exit;
  end;

//  recipientPermissions[0] belongs to the first certificate added.  changeSecurity gives that
//  recipient owner rights, so the file can be managed later.
json := CkJsonObject_Create();
CkJsonObject_UpdateString(json,'method','certificate');
CkJsonObject_UpdateBool(json,'recipientPermissions[0].changeSecurity',True);

jsonOut := CkJsonObject_Create();
success := CkPdf_Protection(pdf,'encrypt',json,jsonOut);
if (success = False) then
  begin
    Memo1.Lines.Add(CkPdf__lastErrorText(pdf));
    Exit;
  end;
Memo1.Lines.Add('method: ' + CkJsonObject__stringOf(jsonOut,'pending.method'));
Memo1.Lines.Add('algorithm: ' + CkJsonObject__stringOf(jsonOut,'pending.algorithm'));
Memo1.Lines.Add('recipients: ' + IntToStr(CkJsonObject_SizeOfArray(jsonOut,'pending.recipients')));

success := CkPdf_WriteFile(pdf,'qa_output/memo_for_recipient.pdf');
if (success = False) then
  begin
    Memo1.Lines.Add(CkPdf__lastErrorText(pdf));
    Exit;
  end;

//  PreLoadCheck says how the file is protected, without loading it.
reader := CkPdf_Create();
info := CkJsonObject_Create();
success := CkPdf_PreLoadCheck(reader,'qa_output/memo_for_recipient.pdf',info);
if (success = False) then
  begin
    Memo1.Lines.Add(CkPdf__lastErrorText(reader));
    Exit;
  end;
Memo1.Lines.Add('saved file, method: ' + CkJsonObject__stringOf(info,'method'));
Memo1.Lines.Add('saved file, recipients: ' + IntToStr(CkJsonObject_SizeOfArray(info,'recipients')));

//  The recipient opens it with the certificate and its private key, here from a .pfx file.
//  (On Windows, a certificate that is installed in the Windows certificate store with its private
//  key is found automatically when the PDF is loaded, and SetDecryptCert is not needed for it.)
myCert := CkCert_Create();
success := CkCert_LoadPfxFile(myCert,'qa_data/pfx/recipient.pfx','pfx-password');
if (success = False) then
  begin
    Memo1.Lines.Add(CkCert__lastErrorText(myCert));
    Exit;
  end;
success := CkPdf_SetDecryptCert(reader,myCert);
if (success = False) then
  begin
    Memo1.Lines.Add(CkPdf__lastErrorText(reader));
    Exit;
  end;
success := CkPdf_LoadFile(reader,'qa_output/memo_for_recipient.pdf');
if (success = False) then
  begin
    Memo1.Lines.Add(CkPdf__lastErrorText(reader));
    Exit;
  end;

empty := CkJsonObject_Create();
loadedInfo := CkJsonObject_Create();
success := CkPdf_Protection(reader,'getInfo',empty,loadedInfo);
if (success = False) then
  begin
    Memo1.Lines.Add(CkPdf__lastErrorText(reader));
    Exit;
  end;
Memo1.Lines.Add('opened with: ' + CkJsonObject__stringOf(loadedInfo,'loaded.openedWith'));
Memo1.Lines.Add('pages: ' + IntToStr(CkPdf_getNumPages(reader)));

//  Sample output:

//  method: certificate
//  algorithm: aes-256
//  recipients: 1
//  saved file, method: certificate
//  saved file, recipients: 1
//  opened with: certificate
//  pages: 2

CkCert_Dispose(recipient);
CkPdf_Dispose(pdf);
CkJsonObject_Dispose(json);
CkJsonObject_Dispose(jsonOut);
CkPdf_Dispose(reader);
CkJsonObject_Dispose(info);
CkCert_Dispose(myCert);
CkJsonObject_Dispose(empty);
CkJsonObject_Dispose(loadedInfo);