Secure contactless smartcard ASIC with DPA protection

Abstract

A secure contactless smartcard is presented. No batteries are required as device power is extracted from the RF field. With the exception of an inductive loop antenna, no external components are required. The transceiver adheres to the ISO 14443 type B specification. This system-on-a-chip integrates the RF circuitry with a large digital circuit without benefit of external bypass capacitors. An isolation circuit is introduced that prevents coupling of digital noise into the receiver. A measured bit error rate of 3E-10 is achieved. Security is also improved as the isolation circuit increases the required time for differential power analysis (DPA) attack by a factor of 2/sup 22/. Three-pass mutual authentication is presented and an algorithm for data restoration in the event of a tear is shown. This device was fabricated in a 0.6-/spl mu/m double-poly, triple-metal CMOS process. The chip is 2.8 mm/spl times/2.9 mm and it requires 500 uA or approximately 2.5 mW of power.