@misc{cryptoeprint:2003:131,
    author = {Kristian Gjøsteen},
    title = {Homomorphic public-key systems based on subgroup membership problems},
    howpublished = {Cryptology ePrint Archive, Report 2003/131},
    year = {2003},
    url = {http://eprint.iacr.org/2003/131},
}