Firmware Authentication and Bridging

NETINT cryptographically signs its firmware images to prevent the installation of corrupted or tampered firmware.

When NETINT compiles the Quadra firmware image, a digital signature is generated for the firmware image using NETINT’s private key. This digital signature is then embedded in the firmware binary file (Example filename for 4.2.0 release would be nor_flash_v4.2.0-Quadra.bin).

Within NETINT’s firmware is also a stored copy of NETINT’s public key. When a firmware image is transferred from the host to Quadra for upgrade consideration, the executing firmware on Quadra will validate the digital signature of the firmware image under consideration. It does this by using the public key stored within the executing firmware on the device. If the firmware image under consideration is validated successfully and passes all other checks, then it will be accepted by the Quadra device as the next firmware image. A power-cycle for cold upgrade, or reset command for warm/temp-upgrade will then cause the new firmware image to be loaded and executed by the device.

The private key used to sign the new firmware image must be compatible with the public key stored in the existing firmware image. This protection prevents Quadra from being loaded with unofficial or corrupted firmware.