In this paper we consider matrices of special form introduced in [11] and used for the constructing of resilient functions with cryptographically optimal parameters. For such matrices we establish
lower bound 1/log2(√5+1) = 0.5902... for the important ratio t/t+k of its parameters and point out that there exists a sequence of matrices for which the limit of ratio of these parameters
is equal to lower bound. By means of these matrices we construct m-resilient n-variable functions with maximum possible nonlinearity 2
n-1-2
m+1 for m = 0.5902 . . . n+O (log2
n). This result supersedes the previous record.
Keywords stream cipher - Boolean function - nonlinear combining function - correlation-immunity - resiliency - nonlinearity - special matrices