Marooned Away From Real Time (was: Announcing E 0.8.4: The Birthday Release)

[Mark S. Miller]

At 03:03 PM 6/1/99 , Tyler Close wrote:
>Ok, I haven't seen a full description of how this takes place, but can Mallet
>additionally leak bits to Bob by putting the table at the edge of a rehash
>operation? Bob can then check the time before and after his insert 
operation to
>see how long it took. Long for a 1 and quick for a 0.

[-] Only if Bob can read the clock.

In order for Alice to be confident that Bob cannot read a covert channel, 
Alice must be sure that none of the non-deterministic inputs to Bob can be 
written by Mallet.  Timing is the most obvious of these, so Alice's first 
step is always to ensure that Bob is denied access to a real clock.