The Cocaine Auction Protocol:
On the Power of Anonymous Broadcast

Frank Stajano and Ross Anderson

Traditionally, cryptographic protocols are described as a sequence of steps, in each of which one principal sends a message to another. It is implicitly assumed that the fundamental communication primitive is necessarily one-to-one, and protocols addressing anonymity tend to resort to the composition of multiple elementary transmissions in order to frustrate traffic analysis.
This paper builds on a case study, of an anonymous auction between mistrustful principals with no trusted arbitrator, to introduce "anonymous broadcast" as a new protocol building block. This primitive is, in many interesting cases, a more accurate model of what actually happens during transmission. With certain restrictions it can give a particularly efficient implementation technique for many anonymity-related protocols.

Frank gave (an evolving version of) the Cocaine Auction talk on the following occasions:

1999-05-25

Security seminar at the University of Cambridge Computer Laboratory, Cambridge, UK.

1999-09-24

Informal short talk at the Friday security group meeting at the University of Cambridge Computer Laboratory, Cambridge, UK.

1999-09-30

The full paper was accepted and presented at the 3rd International Workshop on Information Hiding, held in Dresden, Germany from 1999-09-29 to 1999-10-01. It appears in the proceedings, published in the Lecture Notes for Computer Science series and © Springer-Verlag . As allowed by the © agreement, it may also be downloaded from this page as PDF (with active links, 227 KB) or gzipped PostScript (179 KB).

1999-10-18

Unplanned extension to my scheduled COMET seminar at Columbia University, New York City, NY, USA.

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