@misc{cryptoeprint:2007:223,
    author = {John Black and Martin Cochran and Thomas Shrimpton},
    title = {On the Impossibility of Highly-Efficient Blockcipher-Based Hash Functions},
    howpublished = {Cryptology ePrint Archive, Report 2007/223},
    year = {2007},
    url = {http://eprint.iacr.org/2007/223},
}