Hierarchical Identity-based Broadcast Encryption Scheme on Lattices

In this paper, a hierarchical identity-based broadcast encryption scheme is proposed based on the learning with errors problem, which is a classic hard problem on lattices. In the proposed scheme, each user´s identity is associated with a lattice matrix, then the relationship between the lattice and its sub lattice could easily represent the hierarchical identity construction. Short basis of a lattice can function as a private key of a user, so based on the Sample Basis algorithm the private key of each level´s user can be derived. The security proof of our proposed scheme is also given in this paper, which is IND-CCA2 secure against the attacks by outsider users and FS-CCA secure against the attacks by authorized receivers. In addition, compared with the broadcast encryption scheme based on the bilinear mapping, the scheme in this paper is more efficient in the encryption and decryption.