Economic Costs of Multi-sever Private Information Retrieval in Cloud Computing

Traditionally researchers analyze the performance of different security protocols by studying computation cost and communication cost, however in cloud environment a more comprehensive method to evaluate the performance of security protocols is required. In this paper we propose a new method to evaluate the performance of security protocols in cloud computing. Instead of computation cost and communication cost, we will analyze the economic costs of security protocols in cloud computing. Private information retrieval(PIR) is a privacy enhancing protocol designed to hide access patterns during data retrieval, which makes it useful to protect user´s privacy in cloud environment. While plenty PIR schemes were proposed since this concept was firstly raised in 1995, real economic costs of PIR schemes in cloud environment remain unexplored. In this paper We will revisit typical multi-server PIR schemes in cloud environment under a realistic indicator - economic costs. Our results shows that multi-server PIR schemes have lower economic costs than the trivial solution.