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EN · KO

  1. TESIGN / RADAR
  2. Let's Seal

Let's Seal

Prove a file is unaltered and dated

WHO USES ITSmall businesses and freelancers · Development teams · Photographers and video makers

Use in the browser

Free web app and open SEAL standard that proves a file is unaltered and existed by a date

★ 371▲ 94 HN

371 stars · checked on GitHub GitHub check 30 h late · no 7-day star increase observed (GH Archive) (as of ) · 94 Show HN points observed

BACK CATALOG

The Let's Seal verification portal: a 'Verify a document' heading above a drop zone for a PDF and a field for pasting a SHA-256 fingerprint or proof link
The Let's Seal verification portal: a 'Verify a document' heading above a drop zone for a PDF and a field for pasting a SHA-256 fingerprint or proof link
The Let's Seal verification portal: a 'Verify a document' heading above a drop zone for a PDF and a field for pasting a SHA-256 fingerprint or proof link

TESIGN TAKE

It opens up what paid document-sealing services sell, in standard formats and for free; just remember it is not notarisation or identity verification.

TRY

AT A GLANCE

LICENSE
Apache-2.0
USAGE
Commercial use, redistribution OK. Keep notices; mark changes.
LANGUAGE
JavaScript
PLATFORM
web · cli
ACTIVITY
last commit 2 days ago () · latest release v0.1.0 () · 1 release
COMMUNITY
2 contributors · 18 open issues (incl. PRs) · made by: an individual
SOURCES
Show HN
OPEN SOURCE
YES
FIRST SEEN
CATEGORY
SECURITY

A summary, not legal advice.

WHY IT MATTERS

Once a quote, contract or delivery photo leaves your hands, there has been no easy way to prove later that it is the original and when it was made. Let's Seal embeds a PAdES signature in PDFs and a C2PA manifest in images, video and audio, anchors the time to Bitcoin through OpenTimestamps, and writes every seal to an RFC 6962 transparency log. Sealing and verifying are free, and verification needs no account, at verify.letsseal.org or offline with standard tools.

BUILD FROM THIS

  • Add an automatic sealing step for outgoing PDFs and images through the REST API or the sealbot CLI, or wire the provided GitHub Action into CI to sign build artifacts and attach SBOM attestations.

WHO IT'S FOR

Small businesses and freelancers
seal quotes and contract PDFs to prove they are unaltered
Development teams
sign build artifacts and containers with SBOM attestations in CI
Photographers and video makers
embed C2PA Content Credentials in media files

START IN 5 MINUTES

# # No install: seal at https://app.letsseal.org, verify at https://verify.letsseal.org
# npm i -g sealbot
# sealbot seal contract.pdf          # seal a PDF or any file
# sealbot verify contract.sealed.pdf # verify a seal, offline
# python spec/verify.py sealed.pdf sealed.pdf.ots

CAVEATS

  • Licence Apache-2.0 (the SEAL specification is free to implement). The proof covers integrity, time and the issuing certificate only; the README states it is not notarisation and does not assert a person's legal identity.
  • Self-hosting means running a CA, a Python signing service and a Next.js/Prisma web app yourself, and a paid AATL/eIDAS .p12 certificate is needed if you want third-party PDF readers to show their automatic green check.
  • Started 2026-07 and described as a foundation-run public-benefit project; long-term operating record [확인 필요].

RECEIPT

FIRST SEEN
AT SOURCE
KEPT
CREATED → FIRST SEEN
47d
SOURCES
Show HN
◌ BACK CATALOG
Reconstructed from archive data, not a live discovery.

The same facts in machine-readable form — View as Markdown · JSON

SIMILAR TOOLS

Up to five from SECURITY by ★ total: edited entries first, then repository cards; this entry is highlighted. Drawn from the same stored snapshot as the rankings — a comparison, not a recommendation.

IMAGENAME★ TOTAL▲ 7dLICENSEPLATFORMLAST PUSH
The repository's own benchmark leaderboard: F1, precision, recall, time and tokens per model and review tool, in a dark table.
open-code-reviewAI code review for developers★ 28.6k▲ +1,064Apache-2.0permissivewindows · macos · linux · cli
The Let's Seal verification portal: a 'Verify a document' heading above a drop zone for a PDF and a field for pasting a SHA-256 fingerprint or proof link
Let's SealProve a file is unaltered and datedTHIS ENTRY★ 371—Apache-2.0permissiveweb · cli
ente/enteCARD★ 28.9k▲ +13AGPL-3.0copyleft—
deskflow/deskflowCARD★ 28.8k▲ +5GPL-2.0copyleft—
laramies/theharvesterCARD★ 17.4k▲ +10Licence unconfirmedunconfirmed—

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TIMELINE

  1. Repository created
  2. Show HN post ↗
  3. FIRST SEEN BY TESIGN ◌ BACK CATALOG