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Alan Karp [identifies][1] 11 security questions:

  [1]: http://www.eros-os.org/pipermail/cap-talk/2007-December/009460.html

 * Authentication    Who am I talking to?
 * Authorization     What should I be able to do?
 * Audit                     Who did that?
 * Access control    Should this request be honored?

 * Non-repudiation   Can I pretend I never said that?
 * Confidentiality           Can others see what I'm seeing?
 * Privacy                   Can others see that I'm seeing it?
 * Integrity                 Can this data be changed?
 * Anonymity                 Can others find out who I am?

 * Denial of service         Can I be assured of access?
 * Physical security         Who can touch it?

Mark Miller [proposes][2] some ways to think about security relationships:

  [2]: http://www.eros-os.org/pipermail/cap-talk/2008-March/010615.html

A way to talk about security relationships

Permissions channels (necessarily overt in a sensible system) are phisical:

  * Alice gives Bob a car or a car key.

Online overt information channels are visual:

  * Bob can see Carol. Bob can see Carol's car.
  * (Potential, transitive) overt connectivity is line of sight.
  * Lack of overt connectivity (including revocation) is occlusion.
  * Alice tells the Caretaker to turn opaque, blocking Bob's view of Carol.

Offline overt channels are visual but indirect:

  * Bob can see that Kilroy was here.

Online non-overt channels (both covert & side) are auditory:

  * Bob can hear Carol (e.g., hear Carol banging on the wall)
  * Alice tries to silence (or mute) Carol
  * Alice deafens Bob (or creates a deaf Bob)
  * In order for Bob to hear Carol's wall banging, Bob and Carol,
      must be awake at the same time

Offline non-overt channels are olfactory:

  * Bob can smell that Kilroy was here, even if Kilroy is asleep or dead.