Burn After Reading: Adaptively Secure Puncturable Identity-Based Proxy Re-Encryption Scheme for Securing Group Message

Puncturable proxy re-encryption (PPRE) is envisioned to provide secure access control delegation and fine-grained forward security for asynchronous group messaging systems. Nevertheless, the existing PPRE scheme not only suffers from the burden of certificate management but also merely achieves selective security based on the nonstandard assumption. In this article, a puncturable identity-based PRE (P-IB-PRE) scheme is proposed to efficiently protect the security and privacy of the group message. The proposed scheme introduces a message server as the proxy to transform ciphertext for each participant in the group; thus, the heavy computation overhead is delegated to the message server with abundant resources. Most importantly, our scheme enables the recipient to revoke its private key's decryption capability of the specific messages without affecting other messages. Moreover, the identity-based mechanism eliminates the burden of certificate management as well as improves efficiency. The proposed scheme achieves adaptive security under the standard decisional bilinear Diffie–Hellman (DBDH) assumption. Eventually, theoretical and experimental analyses demonstrate that the proposed scheme has an excellent performance in efficiency and practicality.