Cryptology ePrint Archive: BibTeX Citation of Report 2013/632

@misc{cryptoeprint:2013:632,
    author = {Ahmed Mahmoud and Ulrich Rührmair and Mehrdad Majzoobi and Farinaz Koushanfar},
    title = {Combined Modeling and Side Channel Attacks on Strong PUFs},
    howpublished = {Cryptology ePrint Archive, Report 2013/632},
    year = {2013},
    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.