Mix-ORAM: Using delegate shuffles

TL;DR

This paper introduces Mix-ORAM, a novel approach that delegates eviction in ORAM to semi-trusted third parties, reducing client overhead and making private storage more practical.

Contribution

It proposes four mix-net inspired designs for delegating ORAM eviction, improving practicality and efficiency of private storage solutions.

Findings

Four new Mix-ORAM designs with periodic costs

Delegating eviction reduces client overhead significantly

Enhanced practicality of ORAM for untrusted storage environments

Abstract

Oblivious RAM (ORAM) is a key technology for providing private storage and querying on untrusted machines but is commonly seen as impractical due to the high overhead of the re-randomization, called the eviction, the client incurs. We propose in this work to securely delegate the eviction to semi-trusted third parties to enable any client to accede the ORAM technology and present four different designs inspired by mix-net technologies with reasonable periodic costs.