1.2 Device Features

The ECC204 includes an EEPROM array that can be used to store one private ECC P-256 key, two encoded certificates, one symmetric secret key, miscellaneous read/write data, consumption logging and security configurations. Write access to the various Data zone slots and configuration subzones of memory can be restricted.

The device comes in one of two possible serial interfaces. The I²C version of the device supports a standard I²C interface at speeds of up to 400 kHz. The interface is compatible with the Standard and Fast modes I²C interface specifications. The device also supports a Microchip proprietary PWM Single-Wire Interface (SWI), which can reduce the number of GPIOs required on the system processor and/or reduce the number of pins on connectors. When in SWI mode, the ECC204 can be operated in Parasitic Power mode, reducing the pin count to just two pins.

Each ECC204 unit is shipped with a unique 72-bit serial number. The ECC204 also features a wide array of defense mechanisms specifically designed to prevent physical attacks on the device itself or logical attacks on the data transmitted between the device and the system. Hardware restrictions on how a key is used or generated provide further defense against certain styles of attack.

For those users interested in a higher level of security, a Compliance mode bit is available in the Configuration zone. If the Compliance bit is set, compliance with various aspects of FIPS 140-3 is enforced by the device.

The ECC204 also has a monotonic counter that can be attached to either the ECC P-256 private key or the HMAC key to limit the use of one of these keys. If so desired, the monotonic counter can also be used by the host system.