Some new p-ary two-secure frameproof codes

If C is a p-ary code of length n and a((1)) and a((2)) are two codewords, t hen a((3)) is called a descendant of a((1)) and a((2)) if a(i)((3)) is an e lement of {a(i)((1)), a(i)((2))} for i = 1,...,n. We are interested in code s C with the property that either any two nonintersecting coalitions of siz e 2 have no common descendant or the descendant of any coalition of size 3 does not belong to the code. We construct such codes based on Hadamard matr ices. (C) 2000 Elsevier Science Ltd. All rights reserved.