@misc{cryptoeprint:2008:032,
    author = {Boaz Barak, Mohammad Mahmoody-Ghidary},
    title = {Merkle Puzzles are Optimal},
    howpublished = {Cryptology ePrint Archive, Report 2008/032},
    year = {2008},
    url = {http://eprint.iacr.org/2008/032},
}