If you are interested to know the components of Intel Active Management Technology (AMT) and how the management engine is secured, take a look at the whitepaper "Advanced Security Design Aspects of Intel Active Management Technology"
This is one resource in a collection of materials provided for those designing Intel AMT into embedded solutions. Other resources are available at http://www.intel.com/p/en_US/embedded/hwsw/technology/amt
The Security Design Aspects whitepaper provides insights on the architecture, configuration and communication security, and more. For example - did you know that the base engine is "Intel ME", and that Intel AMT is actually a module\component in addition to Intel ME.