Non-interactive Revocable Identity-Based Access Control over e-Healthcare Records

Revocation of access control on private e-healthcare records (EHRs) allows to revoke the access rights of valid users. Most existing solutions rely on a trusted third party too much to generate and update decryption keys, or require the computations of non-revoked users during the revocation, which make them impractical for some more complicated scenarios. In this paper, we propose a new revocation model, referred to as non-interactive revocable identity-based access control (NRIBAC) on EHRs. In NRIBAC, a trusted third party only needs to generate secret keys for group authorities and each group authority can generate decryption keys for the users in its domain. The NRIBAC distinguishes itself from other revocation schemes by the advantageous feature that it does not require any participation of non-revoked users in the revocation. We construct an NRIBAC scheme with short ciphertexts and decryption keys by leveraging hierarchical identity-based encryption and introducing the version information. We formally prove the security of the NRIBAC scheme and conduct thorough theoretical analysis to evaluate the performance. The results reveal that the scheme provides favorable revocation procedure without disturbing non-revoked users.