Tags.

RFID and barcode tags carry the GS1 identifiers an event observes. The tag is where the identifier originates; the event is what the gateway validates, stamps and hashes once that identifier reaches the door.

POST /capturePOST /translate

One identifier, three spellings, one hash.

urn:epc:id:sgtin:0950600.013435.A1-9      // the EPC URN (RFID era)
(01)09506000134352(21)A1-9                // the element string (label)
https://id.gs1.org/01/09506000134352/21/A1-9  // the Digital Link URI

→ normalize → one canonical form → one CBV §8.9 event hash

Illustrative: the same tagged unit as an EPC URN, an element string, and a GS1 Digital Link URI. The gateway's Digital Link normalization feeds the CBV §8.9 hash, so all three name — and hash — the same object.

For the engineer reconciling tag data to events.

Identifier drift — the same unit spelled three ways by three systems — is why traces used to need a reconciliation meeting. Normalization before hashing makes the spelling irrelevant: the same observed object is the same event identity, whichever reader produced the string.

Get a capture key