3.5.3 Start Operation

During the Start operation, the SRAM start-up values and the activation code that were generated during enrollment are used to reconstruct the intrinsic PUF key. When the activation code of another device is used, reconstruction fails and the PUF module responds with an error indication.

After successful completion of the Start operation, diagnostic information about the PUF quality is provided in the PUF score (see PUF Diagnostics for details).

Note: The PUF scores returned after a Start (or Reconstruct) operation and Enroll (or Test PUF) operation can differ, because these operations measure PUF quality in different ways.
Start operates in two phases:
  • Reconstruction to regenerate the intrinsic PUF key
  • Anti-aging to ensure the reliability and stability of the PUF response over time