Document authenticity is the degree to which a record is genuine, complete, and correctly attributable to the organization or person it names. It is distinct from whether a document merely looks convincing: a file may be altered, incomplete, taken out of context, or falsely labeled.
In cybersecurity, authenticity matters when assessing leaked files, ransomware claims, invoices, contracts, or procurement records. Defenders can compare documents with trusted internal copies and records, verify signatures and metadata, and confirm provenance with relevant teams. A threat-actor listing or a set of plausible-looking documents is not, by itself, proof of a breach or of the claims those documents make. Treat unverified material as a potential exposure signal, while avoiding conclusions about incident scope or impact until it is corroborated.