Chip-level security for an IoT device is achieved by implementing measures that protect the device's hardware, particularly against physical attacks and unauthorized access to debugging ports. Encrypting the JTAG (Joint Test Action Group) interface is a critical step in securing an IoT device at the chip level. The JTAG interface is a standard for testing PCBs (Printed Circuit Boards) and widely used for debugging embedded systems. If left unsecured, it can be exploited to reverse engineer the device firmware or to inject malicious code. Encryption of the JTAG interface ensures that even if attackers gain physical access to the JTAG port, they cannot use it to compromise the device without the encryption key.
References: The response is informed by industry practices for securing IoT devices at the hardware level, including the protection of interfaces and ports that could be exploited if left unencrypted12.