Patent ID: 8553877

Claim:
A computing device-implemented method for executing a round of a substitution table-based cryptographic operation applying n input components of length equal to the length of entries of n substitution tables to produce a round output, the n substitution tables generated in the round by successively applying entry-wise rotations of an initial substitution table, the method comprising, a processor of the computing device: masking each substitution table entry of the initial substitution table with a first mask via a bitwise logical inequality operation to provide a masked substitution table, wherein the first mask comprises n first mask value components equal length, and wherein a result of a bitwise logical inequality operation combining the n first mask components equals zero, obtaining n interim masked substitution table outputs by, for each i th corresponding one of the n input components, accessing a corresponding entry of the masked substitution table, and rotating the corresponding entry by an i th rotation operation; and, combining the n interim masked substitution table outputs to produce round output.