@misc{cryptoeprint:2009:150,
    author = {Long H. Nguyen and Andrew W. Roscoe},
    title = {Efficient group authentication protocols based on human interaction},
    howpublished = {Cryptology ePrint Archive, Report 2009/150},
    year = {2009},
    url = {http://eprint.iacr.org/2009/150},
}