Publicly Verifiable Outsourced Computation with a Key Distribution Centre
This work addresses efficiency issues in outsourced computation for clients with limited computational power, though it is incremental as it builds on existing PVC frameworks.
The paper tackles the problem of redundant pre-processing in publicly verifiable outsourced computation by introducing a Key Distribution Centre to handle key generation and distribution, eliminating unnecessary repetitions when multiple clients use the same functions and servers.
The combination of software-as-a-service and the increasing use of mobile devices gives rise to a considerable difference in computational power between servers and clients. Thus, there is a desire for clients to outsource the evaluation of complex functions to a server and to be able to verify that the resulting value is correct. Previous work in this area of Publicly Verifiable Outsourced Computation (PVC) requires a costly pre-processing stage. However, in many practical situations multiple clients will be interested in the same set of core functions and will make use of the same servers. Thus, the pre-processing phase may be performed many more times than is necessary. In this paper we introduce a Key Distribution Center (KDC) that handles the generation and distribution of the keys that are required to support PVC, thereby eliminating this redundancy. We define a number of new security models and functionalities that arise with the introduction of the KDC, and present a construction of such a scheme built upon Key-Policy Attribute-based Encryption.