@misc{cryptoeprint:2011:588,
    author = {Arpita Maitra and Goutam Paul},
    title = {Four-State BB84 is as Secure as the Six-State Protocol},
    howpublished = {Cryptology ePrint Archive, Report 2011/588},
    year = {2011},
    url = {http://eprint.iacr.org/2011/588},
}