On the trade-off between communication and trust in secure computations

Ref: Frank Piessens, Bart De Decker, Erik Van Hoeymissen and Gregory Neven. At ECOOP Workshop on Mobile Object Systems, Cannes, France, June 13, 2000.

Abstract: In this paper, we show that mobile code technology may prove to be a useful tool in advanced cryptographic protocols for secure distributed computing.

Secure distributed computing addresses the problem of performing a computation with a number of mutually distrustful participants, in such a way that each of the participants has only limited access to the information needed for doing the computation. In the presence of a third party completely trusted by all participants, the problem is trivially solvable. However, this assumption is in many applications non­realistic. Over the past two decades, a number of solutions requiring no trusted third party have been developed using cryptographic techniques. The disadvantage of these cryptographic solutions is the excessive communication overhead they incur.

We will show in this paper how the use of mobile agents employing these cryptographic techniques can provide for a trade­off between communication overhead and trust. The communication overhead problem would be solved if the communicating parties were brought close enough together. Our solution is to use mobile agents to execute the cryptographic protocols. Of course, a mobile agent needs to trust his execution platform, but we show that the level of trust needed in this case is much less than the level of trust needed for a classical trusted third party.