Analysis of Path ORAM toward Practical Utilization

Oblivious RAM is known as a secure protocol for hiding client's access pattern from an untrusted server. However, the current ORAM algorithms still incur large computation, storage and communication overheads. For this reason, investigation of the ORAM limitations and methods to improve efficiency in real-world environments is necessary. In this paper we focus on one of the leading algorithms, Path ORAM, and propose an efficient implementation. Specifically we analyse the selection of encryption algorithms, concluding the use of AES-GCM to avoid duplication of blocks on the server. Also we propose extending Path ORM by using local caching on the client to reduce communication overhead. Experimental results from our Python implementation show key tradeoffs for ORAM design.