@misc{cryptoeprint:2008:389,
    author = {Murat Ak and Kamer Kaya and Ali Aydin Selcuk},
    title = {Optimal Subset-Difference Broadcast Encryption with Free Riders},
    howpublished = {Cryptology ePrint Archive, Report 2008/389},
    year = {2008},
    url = {http://eprint.iacr.org/2008/389},
}