Cryptology ePrint Archive: BibTeX Citation of Report 2011/469

@misc{cryptoeprint:2011:469,
    author = {ChangKyun Kim, Eun-Gu Jung, Dong Hoon Lee, Chang-Ho Jung, and Daewan Han},
    title = {Cryptanalysis of INCrypt32 in HID's iCLASS Systems},
    howpublished = {Cryptology ePrint Archive, Report 2011/469},
    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.