What a time stamp establishes
An electronic time stamp links data to a point in time and provides evidence of their temporal existence. A trust service can stamp a document’s digital fingerprint, which later allows correspondence and integrity to be checked. This differs from writing a date inside a file or relying exclusively on the time shown by its creator’s computer.
Relationship with OSH documents
It can form part of the evidence associated with an assessment, communication or training record. Its usefulness should be analysed alongside authorship, version and approval procedure. Digital evidence in occupational risk prevention is not limited to a technical attribute: it also needs to explain the action documented and who took part.
Ordinary and qualified time stamps
The European eIDAS framework distinguishes electronic time stamps from qualified ones. The latter have the specific requirements and effects provided in Articles 41 and 42, including a presumption concerning date, time and integrity. This status should not be attributed to every timestamp. The specific service and its status in the relevant trusted lists must be verified.
What it does not demonstrate
Stamping a file does not confirm that its content is true, the signer witnessed the facts or the recipient received it. Nor does it establish learning or actual equipment delivery. Each purpose may need other evidence and controls. A reliable date applied to an incorrect document preserves temporal evidence of that incorrect document.
Example of document traceability
In a hypothetical example, an approved version of a procedure and its associated stamp are retained. When the file is retrieved, its correspondence with that evidence is checked and linked to its approval. If someone subsequently edits the document, the new version must be managed as such. Keeping the same filename does not automatically preserve its identity.
Retention and validation
The document, stamp and elements needed to validate the evidence should be retained for the intended period. Technological changes and the service used may require additional preservation measures. Selection is coordinated with document management and competent advice. A time stamp contributes one part of traceability without replacing preventive obligations or independently guaranteeing the outcome of a dispute.
