@misc{cryptoeprint:2012:419,
    author = {Kan Yang and Xiaohua Jia and Kui Ren},
    title = {DAC-MACS: Effective Data Access Control for Multi-Authority Cloud Storage Systems},
    howpublished = {Cryptology ePrint Archive, Report 2012/419},
    year = {2012},
    url = {http://eprint.iacr.org/2012/419},
}