Cryptology ePrint Archive: BibTeX Citation of Report 2013/558

@misc{cryptoeprint:2013:558,
    author = {Kevin Henry and Maura B. Paterson and Douglas R. Stinson},
    title = {Practical approaches to varying network size in combinatorial key predistribution schemes},
    howpublished = {Cryptology ePrint Archive, Report 2013/558},
    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.