Adobe Reader protected mode explained

Here is a series of links to an outstanding explanation of how sandboxing works in Adobe Reader.

Inside Adobe Reader Protected Mode – Part 1 – Design
Inside Adobe Reader Protected Mode – Part 2 – The Sandbox Process
Inside Adobe Reader Protected Mode – Part 3 – Broker Process, Policies, and Inter-Process Communication
Inside Adobe Reader Protected Mode – Part 4 – The Challenge of Sandboxing

Enjoy.