Boaz Barak Oded Goldreich Russell Impagliazzo Steven Rudich Amit Sahai Salil P. Vadhan Ke Yang On the (Im)possibility of Obfuscating Programs. 1-18 2001 conf/crypto/2001 CRYPTO http://dx.doi.org/10.1007/3-540-44647-8_1 db/conf/crypto/crypto2001.html#BarakGIRSVY01