@misc{cryptoeprint:1996:007,
    author = {Moni Naor and Adi Shamir},
    title = {Visual Cryptography II: Improving the Contrast Via the Cover Base},
    howpublished = {Cryptology ePrint Archive, Report 1996/007},
    year = {1996},
    url = {http://eprint.iacr.org/1996/007},
}