Cryptology ePrint Archive: BibTeX Citation of Report 2011/021

@misc{cryptoeprint:2011:021,
    author = {Jae Hong Seo and Jung Hee Cheon},
    title = {Fully Secure Anonymous Hierarchical Identity-Based  Encryption with Constant Size Ciphertexts},
    howpublished = {Cryptology ePrint Archive, Report 2011/021},
    year = {2011},
    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.