Security notions for cloud storage and deduplication

Abstract

Cloud storage is in widespread use by individuals and enterprises but introduces a wide array of attack vectors. A basic step for users is to encrypt their data, yet it is not obvious what security properties are required for such encryption. Furthermore, cloud storage providers often use techniques such as data deduplication for improving efficiency which restricts the application of semantically-secure encryption. Generic security goals and attack models have thus far proved elusive: primitives are considered in isolation and protocols are often proved secure under ad hoc models for restricted classes of adversaries.

We formally model natural security notions for cloud storage and deduplication using a generic syntax for storage systems. We define security notions for confidentiality and integrity in encrypted cloud storage and determine relations between these notions. We show how to build cloud storage systems that satisfy our defined security notions using standard cryptographic components.