@misc{cryptoeprint:2009:141,
    author = {Oriol Farras and Carles Padro},
    title = {Ideal Hierarchical Secret Sharing Schemes},
    howpublished = {Cryptology ePrint Archive, Report 2009/141},
    year = {2009},
    url = {http://eprint.iacr.org/2009/141},
}