GriGsi Proof — Content fingerprints

Text

Paste article text, JSON, or any string. The fingerprint updates as you type (UTF-8). The time shown is when the fingerprint was last computed in your browser.

File

Drop a file or choose one. The file stays on your device. For PDF, PNG, JPEG, GIF we can store the fingerprint inside the file (invisible in normal viewing). For MP4, WebM, and other types we append a small text block at the end of the file (usually players still work; keep a backup before stamping).

Drop a file here
or click to browse

Fingerprint (SHA-256, hex)

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Compare

If a publisher shared a fingerprint (or a small JSON record that contains one), paste it here to see whether it matches what you just computed.

A future public ledger API can list official fingerprints per publisher; today this page is the open tool. Questions: contact or API.

How it works

Three steps anyone can follow — no account required on this page.

1

Turn content into a short code

You give the same words or the same file — you always get the same code. Change a single character and the code changes completely.

2

Publisher shares the code

A newsroom or service publishes the code next to the article, invoice bundle, or video package — not the private file itself.

3

You check at home

Copy what you have, paste it here, and compare. If the codes match, you held the exact same bytes (for a file) or the exact same text (for UTF-8).

For publishers and teams

Articles: fingerprint the canonical body (and metadata you agree on) so readers can spot edits or copies.
Invoices and PDFs: stamp once — the fingerprint and timestamp live inside the PDF (after the normal PDF end marker). PNG/JPEG/GIF use metadata or comment space, not visible watermarks.
Video: MP4/WebM and similar get an appended GriGsi block at the end of the file (one file, no sidecar). Test playback in your target apps after stamping.

Use Tools and the extension for trust checks; use GriGsi Proof when you need a neutral, local fingerprint anyone can verify.