@misc{cryptoeprint:2001:051,
    author = {Ran Canetti, Joe Kilian, Erez Petrank, Alon Rosen},
    title = {Black-Box Concurrent Zero-Knowledge Requires $\tilde\Omega(\log n)$ Rounds},
    howpublished = {Cryptology ePrint Archive, Report 2001/051},
    year = {2001},
    url = {http://eprint.iacr.org/2001/051},
}