DS28E15G+U

Memory

DS28E15G+U is an advanced charge-pump based tiny interface EEPROM secure authenticator from Maxim Integrated that combines a user EEPROM with the secure authentication system. This device supports high memory byte counts (1024 byte EEPROM) with secure authentication enabled through a number of digital security features.

The major application field of the DS28E15G+U is in the secure authentication of devices in the Internet-of-things (IoT) universe. The device helps to assure that the right people and the devices they mission control are communicating with each other. The device is also dynamically programmable (writable) over the I2C interface, which opens the possibility of using devices such as the DS28E15G+U to implement a two or three-factor authentication approach.

The working principle of DS28E15G+U authenticator is as follows. First, the user application will send the challenge code to DS28E15G+U through the I2C port. The DS28E15G+U device then takes the challenge code as input, computes a HMAC digest using the SHA-256 algorithm based on the stored secret key and then sends a response code to the user application. At this point, the user application can verify that the device responding is an authentic device by re-sized the stored secret key to generate its own response and compare it with the response code from the device.

The programming of the secret EEPROM in the device is done by sending a control byte and the 8 bytes of secret data via the I2C port. The control byte enables writing to the EEPROM and SETS the writeable bit in the status byte. The writeable bit MUST be SET for the EEPROM to accept the written data. The data is written to the EEPROM in 8-byte increments and is protected from accidental over-writes. When the EEPROM write is completed, the writeable bit is also cleared.

The DS28E15G+U has two distinct memory regions. The first region, the area called “User EEPROM”, is where the user application data is stored. This region is typically used for storing the device’s configuration settings, such as I2C address, encryption configuration, or user keys. The second region, the “Authentication EEPROM”, is where the secret key is stored that is used for the secure authentication process. This region is typically used for storing the device’s 128 bit secret key in 8-byte increments.

The DS28E15G+U also supports an Advanced Encryption Standard (AES) 128 bit encryption feature, which is used to protect data from being copied from the EEPROM. This feature is enabled through the use of cryptographic keys, which allow only authorized devices to access the memory and prevents unauthorized users from copying the data stored in the EEPROM. The data stored in the EEPROM is encrypted using a generated AES Key, which can then be used to decrypt the data stored in the EEPROM with the corresponding unencrypted AES key.

In summary, the DS28E15G+U is a batteryless EEPROM authenticating device with high memory byte count which provides secure authentication enabled through a number of advanced digital security features. It has two distinct memory regions where user apps data is stored and the 128 bit AES confidential key is stored. Its major application field is in the secure authentication of devices in the internet-of-things universe.