@misc{cryptoeprint:2010:188,
    author = {Yan Zhu and Gail-Joon Ahn and Hongxin Hu and Huaixi Wang},
    title = {Cryptographic Role-based Security Mechanisms based on Role-Key Hierarchy },
    howpublished = {Cryptology ePrint Archive, Report 2010/188},
    year = {2010},
    url = {http://eprint.iacr.org/2010/188},
}