Cryptographic VLSI chip has a significant role to
resist the attacks which is the growing customer concern of
hardware security. Redundancy introduces a great amount of
randomness & non linearity in any kind circuitry
(combinational or sequential). We introduce a new type of
redundancy in sequential circuits to make redundant scan
registers that are indistinguishable with the original scan
registers. They are sequentially undetectable as well as
redundant, which makes it highly secured. The approach is
only to replace the original scan registers to modified
redundant scan registers called RScR.