interface IAppxEncryptionFactory : public IUnknown
{
public:
    virtual HRESULT STDMETHODCALLTYPE EncryptPackage(
        /* [in] */ UINT32 algorithmId,
        /* [in] */ __RPC__in_opt IStream *inputPackageStream,
        /* [in] */ __RPC__in_opt IStream *outputPackageStream,
        /* [in] */ __RPC__in_opt IStream *encryptionSettingsStream,
        /* [unique][in] */ __RPC__in_opt IUri *contentId,
        /* [retval][out] */ __RPC__deref_out_opt IAppxEncryptedPackageWriter **encryptedPackageWriter) = 0;

    virtual HRESULT STDMETHODCALLTYPE EncryptBundle(
        /* [in] */ UINT32 algorithmId,
        /* [in] */ __RPC__in_opt IStream *inputBundleStream,
        /* [in] */ __RPC__in_opt IStream *outputBundleStream,
        /* [in] */ __RPC__in_opt IStream *encryptionSettingsStream,
        /* [unique][in] */ __RPC__in_opt IUri *contentId,
        /* [retval][out] */ __RPC__deref_out_opt IAppxEncryptedBundleWriter **encryptedBundleWriter) = 0;
};

#include <appxpackaging.h>

// Assume you have an IAppxEncryptionFactory* named encryptionFactory

UINT32 algorithmId = /* specify encryption algorithm */;
IStream* inputPackageStream = /* input stream for the package */;
IStream* outputPackageStream = /* output stream for the encrypted package */;
IStream* encryptionSettingsStream = /* stream containing encryption settings */;
IUri* contentId = /* content identifier for the package */;
IAppxEncryptedPackageWriter* encryptedPackageWriter = nullptr;

// Encrypt the package
HRESULT hr = encryptionFactory->EncryptPackage(
    algorithmId, inputPackageStream, outputPackageStream, encryptionSettingsStream, contentId, &encryptedPackageWriter);

if (SUCCEEDED(hr)) {
    // The package was encrypted successfully

    // You can now use encryptedPackageWriter to add files to the encrypted package
    // ...

    // Close the encrypted package writer when done
    encryptedPackageWriter->Close();
    encryptedPackageWriter->Release();
    encryptedPackageWriter = nullptr;
}