Hybrid Protection of Digital FIR Filters

A digital finite impulse response (FIR) filter is a ubiquitous block in signal processing applications and its behavior determined by coefficients. To protect coefficients from an adversary, efficient obfuscation techniques have been proposed, either hiding them behind decoys or replacing key bits. In this article, we initially introduce query attack that can discover the secret of such obfuscated FIR filters, which could not be broken existing prominent attacks. Then, propose first kind hybrid technique, including both hardware logic locking using point function for protection parallel direct transposed forms filters. Experimental results show technique lead to filters with higher security while maintaining complexity competitive superior those locked methods. It also shown protected multiplier blocks are resilient The on different realizations form has promising potential secure design.