Cryptology ePrint Archive: BibTeX Citation of Report 2003/002

@misc{cryptoeprint:2003:002,
    author = {John Proos},
    title = {Imperfect Decryption and an Attack on the NTRU Encryption Scheme},
    howpublished = {Cryptology ePrint Archive, Report 2003/002},
    year = {2003},
    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.