@misc{cryptoeprint:2007:371,
    author = {Chunbo Ma, Jun Ao, and Jianhua Li},
    title = {Group-oriented encryption secure against collude attack},
    howpublished = {Cryptology ePrint Archive, Report 2007/371},
    year = {2007},
    url = {http://eprint.iacr.org/2007/371},
}