Reverse-engineering infrared-based electronic shelf labels
3 days ago
- #Reverse Engineering
- #Electronic Shelf Labels
- #Infrared Communication
- Electronic Shelf Labels (ESLs) use infrared or radio technologies for price and information updates, with some systems lacking encryption or security measures.
- Infrared-based ESLs, like those from Pricer, employ Pulse Position Modulation (PPM) with PP4 and PP16 symbol sets, enabling data transmission via 940nm bursts at 1.25MHz carrier frequency.
- ESL infrastructure includes management servers, base stations, and transceivers; tags have unique PLIDs derived from barcodes, and commands for updates involve specific frames with CRCs and optional keys.
- Security vulnerabilities allow unauthorized price or image changes, tag locking, or firmware updates, though some brands mention security features like AES-128 encryption.
- Tag electronics rely on proprietary ASICs with volatile RAM for firmware, risking irrecoverable loss if power fails, and may include programming contacts for initial setup.