@misc{cryptoeprint:2015:1254,
    author = {Yohei Watanabe and Junji Shikata},
    title = {Identity-based Hierarchical Key-insulated Encryption without Random Oracles},
    howpublished = {Cryptology ePrint Archive, Report 2015/1254},
    year = {2015},
    url = {https://eprint.iacr.org/2015/1254},
}