Cryptology ePrint Archive: BibTeX Citation of Report 2013/215

@misc{cryptoeprint:2013:215,
    author = {Ulrich Rührmair and Christian Hilgers and Sebastian Urban and Agnes Weiershäuser and Elias Dinter and Brigitte Forster and Christian Jirauschek},
    title = {Optical PUFs Reloaded},
    howpublished = {Cryptology ePrint Archive, Report 2013/215},
    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.