@misc{cryptoeprint:2005:334,
    author = {Michael Backes and Christian Cachin and Alina Oprea},
    title = {Secure Key-Updating for Lazy Revocation},
    howpublished = {Cryptology ePrint Archive, Report 2005/334},
    year = {2005},
    url = {http://eprint.iacr.org/2005/334},
}