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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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