Sure, an NDA is a Non-Disclosure Agreement, which will basically outline the fact that your contractors can't reveal any telling details about the running of your business, your clients, your software etc. that you don't first give them permission to do so.

IPR stands for Intellectual Property Rights - by signing over IPR on either a project by project basis, or for any works completed whilst in your paid employ, a contractor gives you sole, (or non-exclusive), rights to all aspects of the project worked on, or to individual parts thereof.