Efficient Revocable ID-Based Encryption with a Public Channel

Abstract

Over the last few years, identity (ID)-based encryption (IBE) without requiring certificate management offers a practical alternative to public key encryption. However, how to revoke misbehaving/compromised identities in ID-based public key setting becomes a new and critical issue. In the past, there was little work on studying this revocation problem. In 2008, Boldyreva et al. proposed a revocable IBE (RIBE) and its associated revocation solution that used a binary tree structure to reduce the authority's periodic workload in Boneh and Franklin's IBE. However, Boldyreva et al.'s RIBE raised enormous computation costs for encryption and decryption procedures. Both IBEs require a secure channel between each user and the authority to transmit user's periodic private keys, thus the authority and each user need to encrypt and decrypt the private keys for each period. In this article, we present an efficient RIBE with a public channel, which provides a practical alternative to the previously proposed revocation solutions, while it remains efficient for encryption and decryption. Under the bilinear Diffie–Hellman assumption, we demonstrate that our RIBE with a public channel is semantically secure against adaptive chosen plaintext attacks and adaptive chosen ciphertext attacks.