How to Print a Secret
In USENIX Workshop on Hot Topics in Security (HotSec), 2009
Aleksander Essex, Jeremy Clark, Urs Hengartner, and Carlisle Adams
Abstract. We consider the problem of how to print a human-readable message, or image, on a piece of paper, while simultaneously preventing the participating printing agents or devices from learning its contents. We examine the problem in two settings: with a trusted dealer who knows the message, and in a distributed scenario that allows two non-colluding printers to obliviously generate the secret message and print it without ever learning it. We present a basic protocol for printing arbitrary-length messages in the trusted dealer model, as well as protocols for printing different types of messages in the distributed model: a randomly selected element from a set, a random permutation of elements in a set, and an optimization for printing alphanumeric characters using 16-segment display logic.
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