1. The “Untrusted” Computer Problem
Matt Burnside, Dwaine Clarke, Blaise Gassend, Tom Kotwal, Sanjay Raman Srini Devadas, Ron Rivest
Marten Van Dijk - Philips

2. Motivation
Wish to use the large screen, keyboard, and high bandwidth of “untrusted” computer
How can we perform secure transactions?

3. Visual Authentication
Computer monitor displays image A, sent by remote application
Human places transparency with image B printed on top of monitor
The composition of Images A and B is what the human sees – Image C
If Image C does not have a certain code, then image A has been corrupted by the computer

4. Visual Authentication

5. Issues
How can we perform authentication of streams of images without compromising the key?
How can we ensure that keyboard requests are not corrupted by the “untrusted” computer?