Collusion-Resistant Identity-based Proxy Re-Encryption: Lattice-based Constructions in Standard Model

TL;DR

This paper introduces the first lattice-based, collusion-resistant, unidirectional identity-based proxy re-encryption schemes secure in the standard model, resistant to quantum attacks, and applicable for both selective and adaptive identities.

Contribution

It provides the first concrete constructions of collusion-resistant unidirectional IB-PRE in the standard model based on learning with error assumptions.

Findings

Secure in the standard model

Resistant to quantum attacks

Applicable for both selective and adaptive identities

Abstract

The concept of proxy re-encryption (PRE) dates back to the work of Blaze, Bleumer, and Strauss in 1998. PRE offers delegation of decryption rights, i.e., it securely enables the re-encryption of ciphertexts from one key to another, without relying on trusted parties. PRE allows a semi-trusted third party termed as a ``proxy" to securely divert encrypted files of user A (delegator) to user B (delegatee) without revealing any information about the underlying files to the proxy. To eliminate the necessity of having a costly certificate verification process, Green and Ateniese introduced an identity-based PRE (IB-PRE). The potential applicability of IB-PRE sprung up a long line of intensive research from its first instantiation. Unfortunately, till today, there is no collusion-Resistant unidirectional IB-PRE secure in the standard model, which can withstand quantum attack. In this paper, we present the first concrete constructions of collusion-Resistant unidirectional IB-PRE, for both selective and adaptive identity, which are secure in standard model based on the hardness of learning with error problem.