Prove you wrote it first.
Timestamp Diary seals what you write the moment you save it. Every entry carries a SHA-256 fingerprint and is chained to the entry before it — so a single edited word breaks the record, and anyone can catch it.
The problem
Someone pitches your idea back to you a month later. Your article gets reposted and the platform asks you to “prove you posted it first.” A colleague presents the concept you sketched last quarter. You know you were first — you just have nothing to show for it.
Here is the awkward part: a file’s “date created” property can be changed in three clicks. Emailing yourself proves nothing. Posting on a platform only timestamps you inside that platform — and it publishes your work at the same time. Notarization works, but at tens of dollars a shot it’s not something you do daily.
What you actually want is cheap, frequent, self-verifiable, and not owned by any single company.
How it works
1 · Your text becomes a fingerprint
The entry body is normalized (line endings unified, trailing newline stripped) and hashed with SHA-256:
content_hash = SHA-256( normalized body )
Change one character — a single space — and the fingerprint changes completely. Not slightly. Completely.
2 · Each entry is chained to the last
At seal time, the entry’s metadata and fingerprint are assembled into a fixed payload and hashed again. Note the final line — it carries the previous entry’s chain fingerprint:
TS-DIARY/v1 author:<name> seq:<sequence number> date:<YYYY-MM-DD> claimed_iso:<ISO 8601 UTC, ms> title:<title> content_hash:<64 lowercase hex> prev:<previous chain fingerprint> chain_hash = SHA-256( payload above )
Every entry bites the tail of the one before it; the first bites a genesis of 64 zeros. That’s a hash chain. Edit any entry and its fingerprint changes, so the next entry’s prev no longer matches — and the break propagates to the end of the chain.
3 · Sealed means sealed
Entries are immutable and undeletable once written to the cloud ledger. This is enforced at the database layer, not by polite front-end convention. There are exactly two things an author can do afterwards: write the next entry, or mark one as public.
4 · The verification is handed to you
This is the part that matters. A system that only vouches for itself is worth nothing. So every public proof page ships with a “re-verify in this browser” button. It recomputes SHA-256 locally using your own browser’s Web Crypto API and compares against the published fingerprints. Nothing is sent to the server — the platform has no way to interfere with the check.
Try it right now. Open any entry in the public gallery, copy the body, run it through any SHA-256 tool — sha256sum, an online hash generator, or ten lines of Python — and compare with the published content_hash. The payload format is published, the algorithm is standard. You don’t have to believe us.
Who it’s for
- Writers, screenwriters, novelists — establish priority before you submit
- Bloggers & content creators — evidence of first publication when your work gets scraped
- Designers & product people — timestamp concepts, specs and prototypes
- Students & researchers — date your ideas, hypotheses and lab notes
- Long-term journalers — a decade of entries that can’t quietly be altered
What it does not do
A tool that hides its ceiling doesn’t deserve your trust.
A hash chain is a self-contained system. It detects single-entry tampering, but it cannot stop someone from recomputing the entire chain from scratch — after which the records are internally consistent again. That is the ceiling of any self-verifying design, not a bug in this one.
The only way past it is external anchoring: submit your chain fingerprint to a third-party timestamp authority (OpenTimestamps, tsa.cn) for an independent attestation. Proof credentials are exportable precisely so you can do this.
It is also not a notary and not a copyright registration. Think of it as a low-cost, high-frequency, self-verifiable time record that corroborates other evidence.
FAQ
Is it free?
Yes. Registration and use are currently free. Every sealed entry gets a content fingerprint and a chain fingerprint, and public proof links can be shared freely.
Do I have to trust the platform?
No. Every public proof page ships with an in-browser re-verification button using your own browser’s Web Crypto API. The payload format is published, the algorithm is standard, and you can reproduce the check with sha256sum or a few lines of code.
Are my private entries published?
No. Entries are private by default. Only entries the author explicitly marks public appear in the gallery or get indexed. This boundary is enforced by database row-level security, not front-end convention.
What can a hash chain actually prove?
It detects any single-entry tampering: change one word and the chain fingerprint no longer recomputes, and anyone running the verification can see it. It does not protect against recomputing the whole chain from scratch. That ceiling is only raised by anchoring the fingerprint to a third-party timestamp authority.
Is this a substitute for copyright registration?
No. It is not notarization and does not replace copyright registration. It is a low-cost, high-frequency, self-verifiable time record that can corroborate other evidence.
Start with today’s entry
Write it, seal it, get a fingerprint and a shareable public link. It takes thirty seconds. You’ll want it later.
Write my first sealed entry →
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