US 9,813,232 B2
Device and method for resisting non-invasive attacks
Toru Katayama, Kanagawa (JP)
Assigned to Cypress Semiconductor Corporation, San Jose, CA (US)
Filed by Cypress Semiconductor Corporation, San Jose, CA (US)
Filed on Mar. 17, 2015, as Appl. No. 14/659,924.
Prior Publication US 2016/0277184 A1, Sep. 22, 2016
Int. Cl. H04L 29/06 (2006.01); H04L 9/00 (2006.01); G06F 7/523 (2006.01)
CPC H04L 9/002 (2013.01) [G06F 7/523 (2013.01); H04L 2209/08 (2013.01)] 6 Claims
OG exemplary drawing
 
1. A semiconductor device for performing cryptographic operations, the semiconductor device comprising:
a random number generator circuit configured to generate a random number;
a controller circuit coupled with the random number generator circuit and configured to determine a bit length based on the random number; and
a multiplier circuit coupled with the controller circuit and configured to perform a multiplication operation within a cryptographic operation to multiply a multiplicand and a multiplier, wherein during the multiplication operation the multiplier circuit is configured to suppress a non-invasive attack by dividing the multiplier into partial units having the bit length determined based on the random number and to multiply the partial units based on the determined bit length, wherein the multiplier circuit comprises a plurality of multiplier modules, wherein the plurality of multiplier modules are configured to multiply in mutually different bit lengths, and wherein the controller circuit is further configured to select one multiplier module from the plurality of multiplier modules in accordance with the random number.