Patent ID: 7913083
Filing Date: 2011-03-22
Classification: H04L

Abstract:
1. A combinatorial key-dependent network for encryption/decryption of input digital data having a first word size into output digital data of the same word size, comprising at least two layers, each layer comprising at least an elementary building block, each building block operating on an input block of bits having a second word size smaller than or equal to said first word size, for generating an output block of bits, said building block comprising: a multiplexer circuit that receives a first portion of said input block of bits and a first set of key bits as inputs, the first portion of said input block of bits operable to select a second set of key bits out of the first set of key bits, wherein the selected second set of key bits are output by said multiplexer circuit, said first portion of bits are transferred intact without modification by an encryption operation to an output of said building block, and the number of bits in the second set of key bits is less than the number of bits in the first set of key bits; and a transformation circuit, for transforming a second portion of said input block of bits into transformed bits according to a reversible transformation chosen, by means of said selected second set of key bits, among a plurality of reversible transformations implemented in said transformation circuit, wherein said transformation circuit transforms said second portion of said input block of bits without receiving said first portion of said input block of bits as an input and said output block of bits comprises the transformed bits followed by said first portion of said input block of bits.