Revocable Identity-Based Encryption with Server-Aided Ciphertext Evolution from Lattices

Revocable identity-based encryption (RIBE) with server-aided ciphertext evolution (RIBE-CE), recently proposed by Sun et al. at TCS 2020, offers significant advantages over previous identity (or key) revocation mechanisms when considering the scenario of a secure data sharing in the cloud setting. In this new system model, the user (i.e., a recipient) can utilize the current short-term decryption key to decrypt all ciphertexts sent to him, meanwhile, the ciphertexts in the cloud evolve to new ones with the aided of the cloud server and the old ones are completely deleted, and thus, the revoked users cannot access to both the previously and subsequently shared data.