Subhamoy Maitra Goutam Paul New Form of Permutation Bias and Secret Key Leakage in Keystream Bytes of RC4. 253-269 2008 FSE http://dx.doi.org/10.1007/978-3-540-71039-4_16 conf/fse/2008 db/conf/fse/fse2008.html#MaitraP08