Anonymous Identity-Based Encryption with Identity Recovery

TL;DR

This paper introduces a novel anonymous identity-based encryption scheme with an identity recovery feature, enabling identity recovery by a designated manager while maintaining security and privacy.

Contribution

It proposes the first AIBEIR scheme combining anonymous IBE with identity recovery, and establishes its security under a new, stronger semantic security model.

Findings

First AIBEIR scheme with security proof

Ensures privacy even when recovery manager is adversarial

Combines anonymous IBE with testable IBE for identity recovery

Abstract

Anonymous Identity-Based Encryption can protect privacy of the receiver. However, there are some situations that we need to recover the identity of the receiver, for example a dispute occurs or the privacy mechanism is abused. In this paper, we propose a new concept, referred to as Anonymous Identity-Based Encryption with Identity Recovery(AIBEIR), which is an anonymous IBE with identity recovery property. There is a party called the Identity Recovery Manager(IRM) who has a secret key to recover the identity from the ciphertext in our scheme. We construct it with an anonymous IBE and a special IBE which we call it testable IBE. In order to ensure the semantic security in the case where the identity recovery manager is an adversary, we define a stronger semantic security model in which the adversary is given the secret key of the identity recovery manager. To our knowledge, we propose the first AIBEIR scheme and prove the security in our defined model.