TY - JOUR A1 - Coster, Matthijs J. A1 - Joux, Antoine A1 - LaMacchia, Brian A. A1 - Odlyzko, Andrew M. A1 - Schnorr, Claus Peter A1 - Stern, Jacques T1 - Improved low-density subset sum algorithms N2 - The general subset sum problem is NP-complete. However, there are two algorithms, one due to Brickell and the other to Lagarias and Odlyzko, which in polynomial time solve almost all subset sum problems of sufficiently low density. Both methods rely on basis reduction algorithms to find short nonzero vectors in special lattices. The Lagarias-Odlyzko algorithm would solve almost all subset sum problems of density < 0.6463 . . . in polynomial time if it could invoke a polynomial-time algorithm for finding the shortest non-zero vector in a lattice. This paper presents two modifications of that algorithm, either one of which would solve almost all problems of density < 0.9408 . . . if it could find shortest non-zero vectors in lattices. These modifications also yield dramatic improvements in practice when they are combined with known lattice basis reduction algorithms. KW - subset sum problems KW - knapsack cryptosystems KW - lattices KW - lattice basis reduction Y1 - 2005 UR - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/4281 UR - https://nbn-resolving.org/urn:nbn:de:hebis:30-12044 SN - 1016-3328 SN - 1420-8954 N1 - Erschienen in: Computational complexity, 2.1992, Nr. 2, S. 111-128 SP - 1 EP - 16 ER -