@misc{cryptoeprint:2001:019,
    author = {Jan Camenisch and Anna Lysyanskaya},
    title = {An Efficient System for Non-transferable Anonymous Credentials with Optional Anonymity Revocation},
    howpublished = {Cryptology ePrint Archive, Report 2001/019},
    year = {2001},
    url = {http://eprint.iacr.org/2001/019},
}