Trusted Integrated Circuit Procurement for Space Assets

ABSTRACT: Crossfield intends to develop a"Chip Firewall"that monitors the I/O (input/output) pins for a tamper circuit activation signal. Side channel attacks, in which one or more pins are forced into a non-legal condition, are a common technique for tampering with or activating a circuit. Using the concept of a firewall, Crossfield intends to monitor the integrated circuit I/O for any illegal condition and then force the integrated circuit into a known state where, 1) no damage is done to the circuit, 2) the circuit can recover more quickly, and 3) any operational condition of the tamper circuit is forced back into a state where it is harmless. Crossfield"s technical approach to implementing the Chip Firewall is based on two innovations, asynchronous logic and DRPs (doped resistance paths). The Chip Firewall can be implemented from standard cells during the trusted fabrication process and is unlikely/very difficult to be detected and/or disable by the entity inserting the tamper circuit. BENEFIT: Crossfield's anti-tamper approach has the benefit of being isolated from the circuit it is monitoring and protecting, so it cannot be easily spoofed itself. The technique does not rely on any information from the circuit itself other than some knowledge of the design at the time the circuit is fabricated. The anti-tamper circuit requires very low chip overhead and can be deployed as a drop-in macrocell. The user does not need to understand the inner workings in order to employ the technique.