Certified timestamp: definition

A certified timestamp is a reliable, precise, hard-to-alter date and time attached to a digital file (photo, screenshot, document) to attest to the exact moment it was produced. It anchors a verifiable moment and strengthens the evidentiary value of a capture. On GroundCam, each capture receives a UTC timestamp, paired with other traceability metadata.

What is a certified timestamp?

A timestamp pairs a date and time with a digital file or event. The whole difference sits in the word "certified". A plain file date stays easy to change — you can reset a device clock or edit an image's properties — whereas a certified timestamp aims for a reliable, traced, hard-to-forge time. "Certified" therefore points to the reliability and traceability of the time source, not a freely editable field.

Criterion	Simple timestamp	Certified timestamp
Time source	Device's local clock	Reliable time reference (UTC)
Editable?	Yes, easily	Hard to alter
Traceability	Weak or none	Traced time origin
Use as evidence	Fragile, disputable	Strengthens evidentiary value

Why does a certified timestamp strengthen a piece of evidence?

A capture gains value when it can answer three questions: what, where, when. A certified timestamp anchors the "when" in a verifiable way. Combined with other metadata — location (GPS), session ID — and a chain of traceability, it makes a capture harder to dispute. On its own, it does not guarantee admissibility: the evidentiary weight of any item depends on the context and on how it is assessed. A timestamp supports traceability; it does not replace that assessment. For more, see the legal validity of a remote assessment.

Certified timestamp vs qualified timestamp: what's the difference?

In a strict legal sense, the European Union defines a "qualified electronic timestamp" under the eIDAS regulation ((EU) No 910/2014). It relies on a trust service provider that binds data to a precise instant. That is a separate framework, distinct from the general notion of a certified timestamp described here: a product that dates its files in UTC does not thereby become a qualified timestamping service under eIDAS.

How does GroundCam timestamp each capture?

Each capture is dated in UTC (Coordinated Universal Time), an international reference that removes time-zone and daylight-saving ambiguity. That timestamp is paired with GPS coordinates and a unique session ID. The goal: a self-contained capture, usable as a traceability element without depending on external context.

These three fields make up the certified metadata attached to each capture. To place the timestamp within the wider setup, see the definition of remote visual assistance.