  The growing sophistication of cyber attacks, vulnerabilities in high
computing systems and increasing dependency on cryptography to protect our
digital data make it more important to keep secret keys safe and secure. Few
major issues on secret keys like incorrect use of keys, inappropriate storage
of keys, inadequate protection of keys, insecure movement of keys, lack of
audit logging, insider threats and non-destruction of keys can compromise the
whole security system dangerously. In this article, we have proposed and
implemented an isolated secret key memory which can log life cycle of secret
keys cryptographically using blockchain (BC) technology. We have also
implemented a special custom bus interconnect which receives custom crypto
instruction from Processing Element (PE). During the execution of crypto
instructions, the architecture assures that secret key will never come in the
processor area and the movement of secret keys to various crypto core is
recorded cryptographically after the proper authentication process controlled
by proposed hardware based BC. To the best of our knowledge, this is the first
work which uses blockchain based solution to address the issues of the life
cycle of the secret keys in hardware platform. The additional cost of resource
usage and timing complexity we spent to implement the proposed idea is very
nominal. We have used Xilinx Vivado EDA tool and Artix 7 FPGA board.
