Zvika Brakerski Jonathan Katz Gil Segev Arkady Yerukhimovich Limits on the Power of Zero-Knowledge Proofs in Cryptographic Constructions. 559-578 2011 TCC http://dx.doi.org/10.1007/978-3-642-19571-6_34 conf/tcc/2011 db/conf/tcc/tcc2011.html#BrakerskiKSY11