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Resource-based Corruptions and the Combinatorics of Hidden Diversity
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BibTeX
@MISC{Garay_resource-basedcorruptions,
author = {Juan Garay and David Johnson and Aggelos Kiayias and Moti Yung},
title = {Resource-based Corruptions and the Combinatorics of Hidden Diversity},
year = {}
}
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Abstract
In the setting of cryptographic protocols, the corruption of a party has traditionally been viewed as a simple, uniform and atomic operation, where the adversary decides to get control over a party and this party immediately gets corrupted. In this paper, motivated by the fact that different players may require different resources to get corrupted, we put forth the notion of resource-based corruptions, where the adversary must invest some resources in order to corrupt a player. If the adversary has full information about the system configuration then resource-based corruptions would provide no fundamental difference from the standard corruption model. However, in a resource “anonymous ” setting, in the sense that such configuration is hidden from the adversary, much is to be gained in terms of efficiency and security. We showcase the power of such hidden diversity in the context of secure multiparty computation (MPC) with resourcebased corruptions and prove that anonymity it can effectively be used to circumvent known impossibility results. Specifically, if OP T is the corruption budget that violates the completeness of MPC (the case when half or more of the players are corrupted), we show that if hidden diversity is available, the completeness of MPC can be made to hold against an adversary with as much as a B · OP T budget, for any constant B> 1. This result requires a suitable choice of parameters (in terms of number of players and their hardness to corrupt), which we provide and further prove other tight variants of the result when the said choice is not available. Regarding efficiency gains, we show that hidden diversity can be used to force the corruption threshold to drop from
Keyphrases
hidden diversity resource-based corruption different player corruption budget atomic operation resource anonymous setting tight variant different resource impossibility result cryptographic protocol resourcebased corruption suitable choice corruption threshold op budget adversary decides full information standard corruption model system configuration secure multiparty computation fundamental difference efficiency gain
