Cryptology ePrint Archive: BibTeX Citation of Report 2011/486

@misc{cryptoeprint:2011:486,
    author = {Kenneth G. Paterson and Jacob C.N. Schuldt and Martijn Stam and Susan Thomson},
    title = {On the Joint Security of Encryption and Signature, Revisited},
    howpublished = {Cryptology ePrint Archive, Report 2011/486},
    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.