André Chailloux Dragos Florin Ciocan Iordanis Kerenidis Salil P. Vadhan Interactive and Noninteractive Zero Knowledge are Equivalent in the Help Model. 467 2007 2007 IACR Cryptology ePrint Archive http://eprint.iacr.org/2007/467 db/journals/iacr/iacr2007.html#ChaillouxCKV07