2 min read
Label 309 Is Now CIP-0190
The Proof of Existence standard we wrote for Cardano has been accepted into the official CIP repository as CIP-0190. Here is what that means, what it does not mean, and what comes next.
Announcements
Posts tagged “label-309”
7 min read
Prove One File from a Merkle Batch: The Inclusion Certificate
After many file hashes are published under one Merkle root on Cardano, an inclusion certificate is a small downloadable file that proves one specific file was part of that batch — checkable in your own browser, with no trust in CardanoWall, forever.
The StandardGuides
9 min read
CardanoWall Returns, Built on Label 309
CardanoWall is relaunching as a Proof of Existence service built on Label 309, an open, vendor-neutral record format for Cardano metadata. Hash, sign, seal, and share content, then verify it without trusting our servers.
Announcements
10 min read
What Is Proof of Existence?
Proof of Existence shows that exact data existed no later than a public timestamp — without publishing the private file itself. Here's how it works and what it does and doesn't prove.
The StandardGuides
11 min read
How Label 309 Works
Label 309 writes a Proof of Existence into Cardano transaction metadata: a content hash first, plus optional signatures, sealed payloads, recipient key slots, and Merkle batches. Here is how each layer works and how anyone verifies it.
The Standard
10 min read
Hash, Sign, Seal, Share: The Four Levels of a CardanoWall Proof
CardanoWall builds proofs in four layers: a plain hash timestamp, an optional signature, an encrypted sealed copy, and private delivery to specific recipients. You use only the layers a situation needs.
The StandardGuides
10 min read
What Goes on the Blockchain When You Make a Proof?
CardanoWall publishes a small proof record on Cardano, not your file. A hash-only proof exposes only a digest, while a sealed proof keeps the content encrypted off-chain — here's exactly what becomes public.
The StandardSecurity
9 min read
Is Label 309 Open Source?
Yes. Label 309 is an open Proof of Existence standard: the code is Apache-2.0, the spec is CC-BY-4.0, and anyone can implement it, fork it, run a gateway, and build products without asking CardanoWall for permission.
The StandardDevelopers
10 min read
Your Identity Is a Seed
A CardanoWall identity is one 32-byte Identity Seed. Save that seed and you can restore your signing and receive keys in any Label 309 tool; lose it and you lose future use of that identity.
SecurityGuides
10 min read
What Is a Receive Address?
A receive address is the public address someone uses to send you a sealed Label 309 record. It is safe to share — unlike your private Identity Seed, which it can never reveal.
GuidesSecurity
10 min read
CardanoWall Desktop: A Local Mail Client for Proofs of Existence
CardanoWall Desktop is an open-source, cross-platform client for Label 309 — local identities, an offline-first record mirror, a sealed inbox, sent-record tracking, and your choice of gateway. Here is how it works.
Guides
10 min read
Do CardanoWall Proofs Work Offline?
Once a Label 309 record, its content, and your keys are synced to your device, CardanoWall Desktop can browse, search, decrypt, and verify them with no network. What it cannot do is fetch data it never cached.
Guides
9 min read
What Is a Label 309 Gateway?
A Label 309 gateway is the publishing service that quotes, uploads, submits, confirms, and indexes Proof of Existence records through a standard API — while your keys stay on your device and proofs verify from public data.
DevelopersThe Standard
9 min read
One Record for Thousands of Files: Merkle Batching
A Merkle root lets one Label 309 record commit to thousands or millions of file hashes, then prove any single item later with a small inclusion proof — without putting every item on chain.
The StandardDevelopers
9 min read
How to Verify a Label 309 Record
Verify a Label 309 proof from the public Cardano chain, the record bytes, and optional content or recipient keys — without trusting CardanoWall or whoever published it.
DevelopersGuides
11 min read
What a Proof of Existence Does Not Prove
A Proof of Existence shows that exact bytes existed by a public time. It does not, on its own, prove ownership, truth, authorship, who was first, legality, or admissibility.
The StandardGuides