This is an excellent taxonomy of the topic, thank you. Authentication is the wing that I'm concerned about -- that is, Authentication of Your Identity, e.g., "what you know" and "what you are", and how certainty and ease-of-use impact your device interaction.

Yeh, I'm a big Schneier fan. :)

Thank you for the pointer to patsmor! I'll go poke at her info page and introduce myself.