id: 02081144 dt: a an: 02081144 au: Shparlinski, Igor E. ti: On the generalised hidden number problem and bit security of XTR. so: Boztaş, Serdar (ed.) et al., Applied algebra, algebraic algorithms and error-correcting codes. 14th international symposium, AAECC-14, Melbourne, Australia, November 26‒30, 2001. \newl Proceedings. Berlin: Springer (ISBN 3-540-42911-5). Lect. Notes Comput. Sci. 2227, 268-277 (2001). py: 2001 pu: Berlin: Springer la: EN cc: ut: ci: li: http://link.springer.de/link/service/series/0558/bibs/2227/22270268.htm ab: We consider a certain generalisation of the hidden number problem which has recently been introduced by {\it D. Boneh} and {\it R. Venkatesan} [Hardness of computing the most significant bits of secret keys in Diffie-Hellman and related schemes, Lect. Notes Comput. Sci. 1109, 129‒142 (1996); Rounding in lattices and its cryptographic applications, Proc. 8th Annual ACM-SIAM on Discrete Algorithms (ACM, New York), 675‒681 (1997)]. We apply our results to study the bit security of the XTR cryptosystem and obtain some analogues of the results which have been known for the bit security of the Diffie-Hellman scheme. rv: