Glossary
Proof of presence
Proof of presence is the verifiable evidence that a guard physically reached a checkpoint. The strongest forms combine three independent signals: a short-range tag read (NFC or Bluetooth), GPS location verification within a tight radius, and a timestamped photo or biometric confirmation. Contracts increasingly specify proof-of-presence requirements rather than scan counts.
Definition
Proof of presence aggregates one or more verification signals at a checkpoint: a passive tag read (QR, NFC, Bluetooth beacon) requires physical proximity to the tag; GPS confirmation requires the device to register inside a defined geofence radius (typically 10-30 m); photo or biometric capture provides a third independent layer. The strongest implementations combine at least two signals — for example, NFC + GPS — making it materially harder to fake than any single technology. The system records the proof package as a single, signed event.
Context
Modern enterprise contracts increasingly specify proof-of-presence requirements explicitly: 'each checkpoint must produce GPS-validated NFC scans with photographic evidence at randomized intervals'. The shift reflects that scan counts alone are gameable — a guard can read a checkpoint tag from a window or have a colleague scan it. Proof of presence raises the bar by requiring multiple independent observations that are hard to spoof simultaneously.
Compliance relevance
SOC 2 CC6 and ISO 27001 A.7.2 increasingly evaluate proof-of-presence quality, not just patrol frequency. Insurance underwriters cite proof-of-presence depth as a premium-affecting variable. Some financial-services and pharmaceutical contracts require two-factor checkpoints (NFC + GPS) by name.