Cryptology ePrint Archive: BibTeX Citation of Report 2014/639

@misc{cryptoeprint:2014:639,
    author = {Mehrdad Majzoobi, Akshat Kharaya, Farinaz Koushanfar, Srinivas Devadas},
    title = {Automated Design, Implementation, and Evaluation of Arbiter-based PUF on FPGA using Programmable Delay Lines},
    howpublished = {Cryptology ePrint Archive, Report 2014/639},
    year = {2014},
    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.