Cryptology ePrint Archive: BibTeX Citation of Report 2010/501

@misc{cryptoeprint:2010:501,
    author = {Frederik Armknecht and Stefan Katzenbeisser and Andreas Peter},
    title = {Group Homomorphic Encryption: Characterizations, Impossibility Results, and Applications},
    howpublished = {Cryptology ePrint Archive, Report 2010/501},
    year = {2010},
    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.