esp32_puflib

ESP-IDF component for SRAM-PUF experiments on ESP32-class microcontrollers. The component measures startup SRAM behavior, stores helper data, and exposes a PUF response API for enrollment and reconstruction workflows.

This component is used as a baseline in did-puf-framework. Treat its output as experimental identity material until the complete enrollment, helper handling, and lifecycle model have been validated for the target deployment.

Integration

Add this directory to the ESP-IDF component search path:

set(EXTRA_COMPONENT_DIRS path/to/esp32_puflib)

Include the public header from application code:

#include "puflib.h"

Partition Requirement

The component stores helper data in NVS during enrollment. The application must provide a partition table with enough NVS space for the target helper data and enrollment metadata.

Review the consuming firmware partition table before changing PUF profile, sample count, or helper format.

Minimal Example

#include "puflib.h"

void app_main(void)
{
    puflib_init();

    if (!is_puf_enrolled()) {
        enroll_puf();
        get_puf_response_reset();
        return;
    }

    puf_response_t response = {0};
    if (get_puf_response(&response) == ESP_OK) {
        /* Use response.bytes within the application trust boundary. */
    }
}

Security Notes

• PUF responses, helper data, and derived keys are sensitive identity material.
• Enrollment must be bound to a lifecycle policy in the consuming system.
• Helper data handling should be reviewed before treating it as public.
• Physical attacks, side channels, and re-enrollment attacks are not solved by this component alone.

License

See LICENSE.