Patent ID: 8422668
Filing Date: 2013-04-16
Classification: G06F,H04L

Abstract:
1. A data processing method comprising: applying a mask to input data to generate masked input data; transforming said masked input data into transformed data using byte substitution implemented using a lookup table (LUT); for mask correction of said transformed data, using said masked input data and said mask in combination to locate an entry in said LUT, said entry corresponding to a transformed and unmasked version of said input data, wherein said masked input data is mapped to said entry in said LUT using an M-to-N decoder that is controlled by said mask, where M is the number of bits in said masked input data and N is the number of entries in said LUT, wherein outputs of said M-to-N decoder are provided as inputs to a cascade of multiplexers, wherein each of said multiplexers is controlled according to a value of a corresponding bit of said mask; and inverting a value of a bit in an output of said M-to-N decoder if a corresponding bit in said mask has a first value, wherein if said corresponding bit has a second value then said bit of said output is not inverted.