SCAR - Scattering, concealing and recovering data within a DHT

This paper describes a secure and reliable method for storing data in a distributed hash table (DHT) leveraging the inherent properties of the DHT to provide a secure storage substrate. The framework presented is referred to as "Scatter, Conceal, and Recover" (SCAR). The standard method of securing data in a DHT is to encrypt the data using symmetrical encryption before storing it in the network. SCAR provides this level of security, but also prevents any known cryptoanalysis from being performed. It does this by breaking the data into smaller blocks and scattering these blocks throughout the DHT. Hence, SCAR prevents any unauthorized user from obtaining the entire encrypted data block. SCAR uses hash chains to determine the storage locations for these blocks within the DHT. To ensure storage availability, SCAR uses an erasure coding scheme to provide full data recovery given only partial block recovery. This paper first presents the SCAR framework and its associated protocols and mechanisms. The paper then discusses a prototype implementation of SCAR, and presents a simulation-based experimental study. The results show that in order for the erasure coding techniques used by SCAR to be effective, P2P nodes must sufficiently available.