Public check of the Previum authorship seal: SHA-256 fingerprint, registration date, server signature and OpenTimestamps receipt.
Before uploading a manuscript to Previum you can register its SHA-256 fingerprint with a date. Any seal can be checked here: enter the fingerprint to see when it was registered.
How to compute the fingerprint of the original file: on Windows, "certutil -hashfile file.docx SHA256"; on macOS or Linux, "shasum -a 256 file.docx". If it matches the registered one, that file existed on that date.
What it proves and what it does not: it proves a file with that fingerprint existed on that date (certain date). It does not prove who wrote it, nor does it replace intellectual property registration. Previum does not keep the manuscript: only the fingerprint.