Since I made the decision to go paperless, I have several months of bank statements that I downloaded and saved in multiple locations...my hard drive and an external drive, and eventually I'll include some cloud services. As I downloaded the statements from my bank, I've saved them as pdf's. My question is can I add security to these existing pdf's now that they have already been created? Or do I need to re-download them and use the pdf security feature built into my mac print queue? Thank you.