Choose the red pill and the blue pill: a position paper

Abstract

In the movie "The Matrix," our hero Neo must choose between taking the Blue Pill and continuing to live in an online, synthesized fantasy world, or taking the Red Pill and joining the real world. The fantasy world appears to those living in it to be full of flowers and trees and big steak dinners, but unknown to them contains malicious Agents who can alter any portion of the world to suit their needs. The real world, in turn, while real, has no visible sun, and the people have only gray mush for food. Authorization and authentication of online transactions across a network requires a trusted path between the user and the server. We posit that those who attempt to solve this problem by creating the trusted path on the general-purpose operating system have taken the Blue Pill and are living in a fantasy world. One simply cannot properly secure a general-purpose operating system. Solving the problem by taking the Red Pill and completely replacing currently used operating systems with ones that we can properly secure does not seem palatable. We suggest a solution that involves taking both the Blue Pill and the Red Pill: providing the trusted path by means of a separate device with a secure operating system, used in tandem with the existing general purpose operating system. Most user interaction occurs on the un-trusted system, with the secure device only being used to finalise transactions. We believe that the technology required for such a device is readily available. Obviously our idea is not a completely novel idea; prior work in the area has had a similar goal. However, most of those attempts have not properly addressed the requirements for the trusted system, generally preferring to use existing general-purpose systems even when on a "dedicated device." [Balfanz 1999] [Kingpin 2001] Others have a very limited scope of use. [Blakely 2004]. We identify a minimum set of requirements for the trusted device. This paper does not provide a working solution (it is a position paper after all); we simply define how one should approach that working solution. Because we advocate a hybrid system it is possible to simplify the trusted system to a point where it would not be usable as a general purpose system, which should make the trusted system rather easier to build and have confidence in.

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