%0 Journal Article %A S. A. Kiselev %A N. N. Tokareva %T On reduction of key space of the cipher A5/1 and on reversibility of the next-state function for a~stream generator %J Diskretnyj analiz i issledovanie operacij %D 2011 %P 51-63 %V 18 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/item/DA_2011_18_2_a4/ %G ru %F DA_2011_18_2_a4