VINCI: Secure test of a VLSI high-speed encryption system

Designers of VLSI circuits for cryptographic applications are faced with a severe dilemma: Concerns of security, requiring encapsulation of cryptographic applications, and testability, requiring access to all hardware subunits to check for their correct functionality, are basically contradictory. A further security requirement is the immediate detection of failure inside the encryption component. In this paper, an approach based on a compound system test strategy is introduced that reconciles the demands of security and testability. This system test strategy based upon built-in self-test on all levels of implementation allows off-line and concurrent checking without opening access to sensitive regions via test structures. The realization of the system test scheme is a new VLSI cipher implementation, VINCI, that fulfills all security demands for immediate failure detection and supports higher level system test strategies