Hierarchical identity-based broadcast encryption

Abstract

We elaborate Hierarchical Identity-Based Encryption (HIBE) with a new primitive referred to as Hierarchical Identity-Based Broadcast Encryption (HIBBE). Similar to HIBE, HIBBE organizes users in a tree-like structure and users can delegate their decryption capability to their subordinates, which mirrors hierarchical social organizations in the real world. Unlike HIBE merely allowing a single decryption path, HIBBE enables encryption to any subset of the users and only the intended users (and their supervisors) can decrypt. We define ciphertext indistinguishability against adaptively chosen-identity- vector-set and chosen-ciphertext attack (IND-CIVS-CCA2) which captures the most powerful attacks on HIBBE in the real world. We construct an efficient HIBBE scheme against chosen-identity-vector-set and chosen-plaintext attack (IND-CIVS-CPA). The construction is built from composite order bilinear pairings and has constant size ciphertext. Analyses show that our HIBBE is efficient in terms of communication and computation that is suitable into practical usage. © 2014 Springer International Publishing Switzerland.