Office of Technology Transfer – University of Michigan

Protecting Bus-Based Hardware IP by Secret Sharing

Technology #3948

Questions about this technology? Ask a Technology Manager

Download Printable PDF

Igor Markov
Managed By
Drew Bennett
Associate Director - Software Licensing 734-615-4004
Patent Protection
US Patent Pending


As designs become more complex and on-chip transistor counts reach into the billions, the designer’s skills, methodologies, and tools are the invaluable assets of semiconductor design houses. This is particularly true for the small and medium-sized fabless design companies. The current trust models and royalty agreements do not fully protect the rights of the designers. The hardware IP providers pay the expenses of masks for their designs, trusting that the foundry would not make additional copies outside the contract. The ready availability of masks, low cost of silicon, and lack of IP owner’s control over the manufacturing flow facilitates illegal copying of ICs. Furthermore, IC packaging obscures the chip’s internals and makes it difficult to trace the owner of IP rights.


Researchers at University of Michigan have created a novel bus-based IC protection method that can authorize the activation of each individual chip and hence can control the number of working chips that contain the designer’s IP. The method leverages bit permutations and substitutions that scramble the bus using a key unique to each IC. The scrambling renders the IC unusable for anyone who does not have the specific key for the chip. Only the owner of IP rights with access to design details can compute the shared key required to unlock (unscramble) the bus and to make the IC usable. In addition, this design also makes an eavesdropper who records all communications between the chip and the unlocking authority unable to compute the key.

Applications and Advantages


  • IP protection for a broad class of integrated circuits


  • IP protection
  • Highly resilient against attacks
  • Low overhead