In this setting, we achieve concurrent Zero Knowledge (cZK) with sub-logarithmic round complexity. Our security proof is (necessarily) non-black-box, our simulator is "straight-line" and works as long as the number of rounds is \omega(1).
We further show that unlike previously studied relaxations of the standard model (e.g., bounded number of sessions, timing assumptions, super-polynomial simulation), concurrent-secure computation is still impossible to achieve in the Bounded Player model. This gives evidence that our model is "closer" to the standard model than previously studied models, and study of this model might shed light on constructing round efficient concurrent zero-knowledge in the standard model as well.Category / Keywords: cryptographic protocols / concurrent zero knowledge Date: received 17 May 2012, last revised 31 Aug 2012 Contact author: ivan visconti at gmail com Available format(s): PDF | BibTeX Citation Note: 31/05/12 Updated acknowledgements. Version: 20120901:044548 (All versions of this report) Short URL: ia.cr/2012/279 Discussion forum: Show discussion | Start new discussion