Encrypt, Decrypt and set Privileges on PDF documents

Set Privileges on an Existing PDF File

In order to set privileges on an existing PDF document, you can use Document->Encrypt(…) method, which takes DocumentPrivilege object. A DocumentPrivilege class is used to set different privileges to access PDF document. Furthermore, there are 4 following ways using this class:

1. Using predefined privilege directly.
2. Based on a predefined privilege and change some specific permissions.
3. Based on a predefined privilege and change some specific Adobe Professional permissions combination.
4. Mixes the way 2 and way 3.

Following code snippet will demonstrate above 4 ways to set document privileges:

For complete examples and data files, please go to https://github.com/aspose-pdf/Aspose.Pdf-for-C
// Load an existing PDF document
auto doc = MakeObject<Document>(L"..\\Data\\SecurityAndSignatures\\input.pdf");

// Way1: Using predefined privilege directly.
System::SharedPtr<Aspose::Pdf::Facades::DocumentPrivilege> privilege = Aspose::Pdf::Facades::DocumentPrivilege::get_Print();
doc->Encrypt(L"user", L"owner", privilege, CryptoAlgorithm::AESx128, false);
doc->Save(L"..\\Data\\SecurityAndSignatures\\SetPrivelegesWay1_out.pdf");

// Way2: Based on a predefined privilege and change some specifical permissions.
System::SharedPtr<Aspose::Pdf::Facades::DocumentPrivilege> privilege2 = Aspose::Pdf::Facades::DocumentPrivilege::get_AllowAll();
privilege->set_AllowPrint(false);
privilege->set_AllowModifyContents(false);
doc->Encrypt(L"user", L"owner", privilege2, CryptoAlgorithm::AESx128, false);
doc->Save(L"..\\Data\\SecurityAndSignatures\\SetPrivelegesWay2_out.pdf");

// Way3: Based on a predefined privilege and change some specifical Adobe Professional permissions combination.
System::SharedPtr<Aspose::Pdf::Facades::DocumentPrivilege> privilege3 = Aspose::Pdf::Facades::DocumentPrivilege::get_ForbidAll();
privilege->set_ChangeAllowLevel(1);
privilege->set_PrintAllowLevel(2);
doc->Encrypt(L"user", L"owner", privilege3, CryptoAlgorithm::AESx128, false);
doc->Save(L"..\\Data\\SecurityAndSignatures\\SetPrivelegesWay3_out.pdf");

// Way4: Mixes the way2 and way3
System::SharedPtr<Aspose::Pdf::Facades::DocumentPrivilege> privilege4 = Aspose::Pdf::Facades::DocumentPrivilege::get_ForbidAll();
privilege->set_ChangeAllowLevel(1);
privilege->set_AllowPrint(true);
doc->Encrypt(L"user", L"owner", privilege4, CryptoAlgorithm::AESx128, false);
doc->Save(L"..\\Data\\SecurityAndSignatures\\SetPrivelegesWay4_out.pdf");