Authors:
Shubham Raj
;
Snehil Joshi
and
Kannan Srinathan
Affiliation:
Centre for Security, Theory and Algorithmic Research, International Institute of Information Technology, Hyderabad, India
Keyword(s):
Privacy, Blockchain, Private Information Retrieval, Private Information Retrieval-Writing, Distributed Database, Packed Secret Sharing, Privacy Enhancing Technology.
Abstract:
Encrypted data is susceptible to side-channel attacks like usage and access analysis. Techniques like
Oblivious-RAM (ORAM) and privacy information retrieval and writing aim to hide clients’ access pattern
while accessing encrypted data on a distrusted server. However, current techniques are constructed for a single
server model making them unsuitable and inefficient for contemporary distributed architectures. In our work,
we address this problem and provide a solution to private information update using packed secret sharing. Our
protocol, named “Private Information Update for Distributed Infrastructure” PIUDI, aims to mitigate the attacks to which PIR-Writing protocols are more susceptible in a distributed environment. Our scheme is secure
in presence of up to t + k − 1 compromised parties where k is the size of the data set. We also provide an
analysis of our protocol for computational efficiency and gas cost in blockchains