The vault.
A SHA-256 hash is a 64-character fingerprint of a file. Alter one character of the file and the fingerprint changes entirely; the fingerprint does not directly expose the document's contents. Anchoring puts the fingerprint on a public record; the draft itself stays with you, and nothing about its contents is posted anywhere. Proving that the draft existed at that moment comes later and takes two files, the draft and its proof, handed to whoever is asking — the fingerprint alone establishes nothing about a document no one has seen. Applied at the end of each writing session, the practice accumulates a dated record that particular files existed at particular times — which does not verify authorship or authentic development, as the limits below spell out.
The short version
- Finish writing. Save the draft. Don't change it again.
- Hash it below. Copy the code.
- Add one line to a log: date, file name, code.
- Stamp the same file at opentimestamps.org. Save the .ots file beside the draft.
- Next session, work in a new copy. Repeat.
- If your work is questioned, hand over the drafts in date order. If someone says you backdated one, hand over that draft and its .ots, and let them check it themselves.
The hasher
This tool reads a file and gives back its fingerprint. Pick a draft below, or drag it onto the box. In a second or two, a 64-character code appears. Copy that code and save it — that is the whole job of this tool.
Your file stays on your computer. The math runs inside your browser, so nothing is uploaded and nothing is stored here. If you want to prove that, turn off your wi-fi and try it: it still works. You can also read the code that does it by viewing this page's source.
SHA-256 fingerprint
CopiedAnchoring
- Record
Keep a running list in a plain document. Add one line each time: the date, the file name, and the fingerprint. Then save the draft file and do not change it. The fingerprint only matches that exact version, so if you edit the file later, save the edited copy under a new name and hash it again.
- Anchor
Go to opentimestamps.org and give it the same file. It hands back a small proof file ending in .ots. Save that file in the same folder as your draft. This step is what puts a public date on your fingerprint, and it is free, with no account to make and no company to depend on, including this one.
- Repeat
Do this at the end of every writing session. One fingerprint says little. Ten of them, spread over three weeks, show a paper trail of a draft growing over time, and anyone can check them years later.
What to do when someone asks
The 64-character code is not, by itself, the proof. The proof is three things kept together: the draft file exactly as it was when you hashed it, the .ots file you got back from OpenTimestamps, and the line in your log giving the date. Keep all three in one folder per draft. If any one of them goes missing, the other two prove much less.
Do not edit a file after you hash it. Changing even one character makes the old fingerprint stop matching, and the proof no longer applies to anything you still have. Keep writing in a new copy with a new name, and hash that one at the end of the session. That is what builds the sequence.
When a professor or committee asks about your work, hand over the drafts themselves, in date order, not the list of codes. A reader can see a paper growing across ten dated files. Almost no one will check a fingerprint, and a page of codes answers a question nobody asked.
The proofs are for the harder moment: someone says a draft was written after the fact, or backdated. Then you give that person two files, the draft and its .ots, and they check the pair themselves at opentimestamps.org. It is free, takes a minute, and needs no account. If the file has not been altered, the check reports the date its fingerprint was locked in. If it has been altered, the check fails, which is the point: nobody has to take your word, or ours.
What a timestamp does not prove
A timestamp sequence documents that particular files existed over time. It does not establish who created them, how they were created, or whether their development was authentic; a determined fabricator could generate text by machine and stamp it in stages, and staged files with scheduled stamping can even be automated. What the practice holds is one property no detector score offers: every element is verifiable by the party judging it, with no trust in this site required.
Platform version histories remain strong evidence in their own right. The vault practice exists because those histories sit on a vendor's servers under a vendor's retention policy, while the fingerprint log sits with the writer.
Complete as it stands
The practice on this page requires nothing further from this site: the hasher, the log, and OpenTimestamps are the whole instrument, free and inspectable, and they work with this site gone. Nothing here is sold, and nothing on this site will ever hold custody of drafts, hashes, or logs; an instrument whose value is that no one has to trust its maker cannot come with an account.