Sciweavers

JOC
2008

Lower Bounds and Impossibility Results for Concurrent Self Composition

13 years 5 months ago
Lower Bounds and Impossibility Results for Concurrent Self Composition
In the setting of concurrent self composition, a single protocol is executed many times concurrently by a single set of parties. In this paper, we prove lower bounds and impossibility results for secure protocols in this setting. First and foremost, we prove that there exist large classes of functionalities that cannot be securely computed under concurrent self composition, by any protocol. We also prove a communication complexity lower bound on protocols that securely compute a large class of functionalities in this setting. Specifically, we show that any protocol that computes a functionality from this class and remains secure for m concurrent executions, must have bandwidth of at least m bits. The above results are unconditional and hold for any type of simulation (i.e., even for non-black-box simulation). In addition, we prove a severe lower bound on protocols that are proven secure using black-box simulation. Specifically, we show that any protocol that computes the blind signatu...
Yehuda Lindell
Added 13 Dec 2010
Updated 13 Dec 2010
Type Journal
Year 2008
Where JOC
Authors Yehuda Lindell
Comments (0)