Differential Defense Against Distributed Timing Attack for Privacy-Preserving Information Centric Network

In-network content caching is a key feature of Information Centric Network (ICN), which facilitates efficient content distribution with reduced bandwidth consumption, less network congestion, and improved content retrieval latency. However, this ubiquitous caching of ICN is vulnerable to side-channel timing attack, where the adversary takes advantage of the response time difference between the cached and un-cached contents from the router, to detect if a privacy-sensitive object is cached, or even infer which user requested the object. To mitigate this type of privacy risk in ICN, we propose a differential defense mechanism against distributed timing attack in this paper. Specifically, we design an algorithm based on differential privacy to determine whether a cache-hit or cache-miss is returned for a certain request, which effectively hide the actual cache hit with differential privacy guarantee. Furthermore, a differential delay algorithm for artificial cache miss is implemented based on Laplace mechanism of differential privacy. Performance analysis and simulation results show that our scheme is more effective against distributed timing attack and incurs less impact on caching efficiency and delay performance compared with existing defense schemes for ICN.