Cryptology ePrint Archive: BibTeX Citation of Report 2006/368

@misc{cryptoeprint:2006:368,
    author = {Man Ho Au and Joseph K. Liu and Tsz Hon Yuen and Duncan S. Wong},
    title = {Practical Hierarchical Identity Based Encryption and Signature schemes Without Random Oracles},
    howpublished = {Cryptology ePrint Archive, Report 2006/368},
    year = {2006},
    note = {\url{http://eprint.iacr.org/}},
}

You will need the url.sty package (comes with most LaTeX installations) for the last line. Otherwise, remove the \url command.