Let's Seal is built from public, boring, checkable standards. These posts explain the decisions behind them, one at a time, and show you how to verify each claim yourself.
A seal proves what a file is. Proving when it existed is the harder problem, because a timestamp is only as trustworthy as the clock behind it. Here is why we anchor to a public ledger, a clock everyone shares and no one owns, and how it stays free.
ReadEvery seal is a leaf in an append-only Merkle tree, the same structure Certificate Transparency and sigstore use. Here is why, and how you can prove for yourself that the log only ever grows.
ReadAdobe's green check means one specific thing: your certificate paid to join a private trust list. We are the free, open alternative, so our mark is blue. Here is exactly what that blue claims, and where it sends you to check.
ReadA PDF, an image, an email and a container image each carry a signature in their own native standard, and every one chains to a single root. Here is why we sign each in its own language, and the one rule that catches tampering.
ReadMost certificate authorities want to live in your operating system and your browser. Ours takes a different path: you pin it yourself, by fingerprint. Here is why that is the more honest design.
ReadEvery seal gets a short code like 5X9H-KWF3-JTBC-55CS-6Q6X. It is independent random data, and that is the point: it keeps the document private, and it doubles as an unguessable key to the proof.
ReadThe spec is CC-BY, the code is Apache-2.0, and verifying a seal runs on public tools alone. Every seal stays checkable on its own, for good. Here is why we built it to outlive us.
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