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Currently even the person checking if a document/contract is sealed or code is authentic has to also be inside the same Adobe walled garden too. Verification, the part that should be free is the part everyone charges for. Thats the shape Let's Encrypt fixed for TLS, and I wanted the same thing for documents and files.
The core idea therefore needed to go a bit beyond e signatures and i created an open standard (SEAL), plus free tools that implement it.
When you seal a file, three independent things happen.
1. it gets a signature from a certificate authority, chaining to a public root. 2. its record is appended to an RFC 6962 transparency log. and 3. its SHA256 is timestamped on a public blockchain (Bitcoin) via OpenTimestamps. Those three give you integrity, transparency and a timestamped proof. And importantly, none of those depend on Let's Seal and none are gated.
You can verify with the tools you already have, no Let's Seal account and no Let's Seal software. A sealed PDF carries a standard PAdES signature, so any PDF reader validates it. A sealed build artefact carries a cosign compatible signature and a SLSA provenance attestation. The Bitcoin timestamp verifies with stock ots.
3 ways to use it.
1. The free web app. We kindly have backing from Backblaze to cover storage costs for the foreseeable. So you can upload or issue any number of documents, get a public proof page at /d/<hash> and verify it at https://verify.letsseal.org for free. Multiple accounts, multiple seats, enterprise functions. Free.
2. Self host the whole thing. Apache-2.0, one Next.js app plus a signing service that holds the CA key on localhost. Storage is any S3-compatible bucket or local disk. If you'd rather run your own root of trust, you can.
3. Programmatically. via the CLI and a hosted API. This is the Let's Encrypt/certbot angle. Seal or anchor things from CI, or have a backend seal every invoice or report as its generated.
The CLI is sealbot. It runs anywhere Node runs (npx sealbot) and there are native binaries for macOS, Linux and Windows with no runtime needed.
Theres a GitHub Action wrapping the same tool, so a release workflow can seal its own artifacts. Its what proves our own releases.
KYC is semi-handled (to a degree) it's hard to do for free (at least for now), but issuers (your companies or websites) domains can be authenticated with a DNS record added, which proves the issuer has control over a domain. Sign-in can be authenticated to an email via Google Sign in and a few others will be added to the web app in time (Same as Docusign currently). Ideas welcome on future KYC should there be a demand.
Feedback welcome on the standard (SPEC.md in the repo).
Repo: https://github.com/letsseal/letsseal Site: letsseal.org
Thx
Discussion (11 Comments)Read Original on HackerNews
Currently courts will still consider paper-signed and scanned PDFs as legally binding, so any verification on top of that is superfluous to them.
More realistically, you take an oauth when you take the stand at the court, and if a signed document was altered by the counterparty you'd say so truthfully, if it weren't, you'd say so truthfully, and the penalty of that oauth purjury is high enough that most people wouldn't do it. Cryptography not needed.
Just a quick note, Under "Get help from the community > Disucssions", there's a 404 to https://github.com/letsseal/letsseal/discussions .
The idea makes sense in principle I think, and but I'll be chewing on it a bit, haha. Seems like a solid standard, but you know how standards go.... (Relevant XKCD: https://xkcd.com/927/)
I like that you kept a lot of the same commands/naming/syntax from LetsEncrypt. As someone familiar with LetsEncrypt, makes me feel like I'd slide right in here easily.
I'd like to learn more about the 'Bitcoin anchored root'...is that part of RFC 6962 or something else entirely? Do you mean a 'Bitcoin-like blockchain' or are you using the actual BTC chain? Could you point me in the right direction?