Apostol Natsev, Alexander Haubold, et al.
MMSP 2007
We show that any concurrent zero-knowledge protocol for a nontrivial language (i.e., for a language outside BPP), whose security is proven via black-box simulation, must use at least Ω̃(log n) rounds of interaction. This result achieves a substantial improvement over previous lower bounds and is the first bound to rule out the possibility of constant-round concurrent zero-knowledge when proven via black-box simulation. Furthermore, the bound is polynomially related to the number of rounds in the best known concurrent zero-knowledge protocol for languages in NP (which is established via black-box simulation).
Apostol Natsev, Alexander Haubold, et al.
MMSP 2007
Ruixiong Tian, Zhe Xiang, et al.
Qinghua Daxue Xuebao/Journal of Tsinghua University
N.K. Ratha, A.K. Jain, et al.
Workshop CAMP 2000
S.M. Sadjadi, S. Chen, et al.
TAPIA 2009