The DS2705 provides the master side of a Secure Hash Algorithm (SHA) based token authentication scheme. Hardware-based SHA authentication allows for security without the added cost and complexity of a microprocessor-based system. Batteries and other accessories are authenticated using a single contact through the Dallas 1-Wire interface. Authentication is performed on demand or automatically, with the pass/fail status reported on open-drain output pins to signal the charge system and/or drive LEDs. The DS2705 stores a predetermined challenge-andresponse pair in nonvolatile (NV) EEPROM. The DS2705 works in conjunction with Dallas Battery Management SHA-1 token products, including the DS2703 and DS2704.