Announcements, guides, and notes from the CardanoWall team — about the product and the open standard Label 309.
9 min read
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
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
12 min read
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
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
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
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
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
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
Share a receive address. Your client scans the public Label 309 feed and locally decrypts the records your keys can open — no server-side mailbox, no recipient list on chain.
GuidesSecurity
10 min read
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
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
10 min read
In CardanoWall, signing, sealing, and decryption all happen locally — the gateway publishes proofs and stores ciphertext but is designed never to receive your private keys.
Security
9 min read
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
10 min read
The website is one interface, not the whole product. You can publish and verify Label 309 records through a CLI, SDKs, a gateway API, a desktop app, or your own service.
DevelopersGuides
9 min read
Publishing a CardanoWall proof costs money because the gateway pays real Cardano transaction fees and, for files, real Arweave storage — then adds a service margin to run a hosted service. Verifying stays free and needs no server.
GuidesDevelopers
9 min read
Yes — a company or developer can run their own Label 309 gateway, fund its Cardano and storage wallets, and publish standard proofs of existence without using CardanoWall as the hosted operator. Here is what that takes.
Developers
9 min read
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
8 min read
A CI/CD pipeline can hash its build artifacts, SBOMs, logs, and release manifests, batch them into one Merkle root, and publish a single Label 309 proof — an independent public time anchor for later audits.
Developers
9 min read
Hash each AI output, prompt, manifest, or Content Credentials record, batch the hashes into Merkle roots, and publish timestamped Label 309 commitments — proving any single item existed without putting every asset or private prompt on chain.
AI & ProvenanceDevelopers
9 min read
Commit a private dataset snapshot to a hash or Merkle root and publish one timestamped proof. The data stays private; later you can selectively prove a file, row, or version was in the committed set.
AI & ProvenanceSecurity
10 min read
Anchor a Merkle root of your compliance evidence on Cardano, and an auditor can later confirm a specific report or log was committed by a public time — without trusting the system that produced it.
Compliance & LegalDevelopers
7 min read
A Merkle root anchored with a Label 309 timestamp lets you commit to a snapshot of reserves, liabilities, or evidence and prove inclusion to individual customers — without publishing every account.
Compliance & LegalDevelopers
8 min read
Sealed Label 309 records timestamp encrypted evidence on Cardano and deliver it to specific recipients, so the timeline is public while the plaintext stays confidential.
SecurityCompliance & Legal
9 min read
A sealed Label 309 record can timestamp encrypted evidence and deliver it to one chosen recipient — but it does not make you anonymous or replace legal and safety advice. Here is what it does and does not do.
Compliance & LegalSecurity
9 min read
How to use Label 309 Proof of Existence to prove a document or discovery export existed by a public time and still matches its original bytes — and where that proof stops and legal process begins.
Compliance & Legal
10 min read
How a security team can timestamp and seal incident evidence as it is collected — a durable, independently verifiable timeline that proves what existed when, without publishing sensitive details.
SecurityCompliance & Legal
8 min read
C2PA describes where media came from; Label 309 anchors the asset or its manifest to an independent public Cardano timestamp. Here is how the two layers fit together.
AI & ProvenanceThe Standard
8 min read
Hash a dataset manifest, batch it with a Merkle root, and anchor it on Cardano with Label 309 — so you can later prove what a dataset snapshot contained without publishing the dataset.
AI & ProvenanceDevelopers
8 min read
Hash your source files, drafts, prompts, exports, or whole project folders and publish a timestamped Label 309 proof that they existed by a given time — without making the work public.
AI & ProvenanceGuides
7 min read
A Label 309 proof shows that a media file existed by a public time. Authenticity needs more: capture context, provenance, signatures, and human verification. Here is how the timestamp layer fits.
AI & Provenance
9 min read
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
9 min read
Your first Label 309 proof can be a hash-only record: hash a file, get a price quote from a gateway, publish the digest on Cardano, and keep the transaction hash. Here is the full workflow.
GuidesDevelopers
10 min read
How to build your own product on CardanoWall: quote, upload, publish, read, verify, and monitor Label 309 records through the same gateway API CardanoWall itself runs on.
Developers
7 min read
Run Proof of Existence from a script: the cardanowall CLI puts JSON on stdout, diagnostics on stderr, gives you stable verification exit codes, takes secrets safely, and publishes through any Label 309 gateway.
Developers
10 min read
A Label 309 gateway is the publishing engine behind a Proof-of-Existence product: it owns Cardano submission, storage, balances, indexing, and webhooks, so your product can own the user experience instead.
Developers
11 min read
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
7 min read
Both bind data to a point in time, but a Timestamp Authority roots trust in a named provider's key, while a Label 309 Proof of Existence roots it in public Cardano consensus. Here's how to choose.
The StandardCompliance & Legal
8 min read
C2PA describes the provenance of a media asset; Label 309 anchors a timestamped commitment to its bytes on Cardano. Here is what each one proves, and why most workflows want both.
The StandardAI & Provenance
7 min read
Sigstore signs software artifacts and logs the event publicly; Label 309 adds an independent blockchain time anchor over your whole release evidence. They solve different problems and work well together.
The StandardDevelopers
9 min read
OpenTimestamps is excellent for bare, Bitcoin-anchored timestamps. Label 309 adds a Cardano-native proof record with signatures, sealing, recipients, and Merkle batching — here is how to choose.
The Standard
9 min read
CardanoWall stores your identity as encrypted vault ciphertext, never plaintext seeds. Here is exactly what the server holds, what only your passkey can open, and why your seed is the real backup.
Security
8 min read
A passkey does not become your CardanoWall identity — it unlocks an encrypted vault that only your authenticators can open. Here is how WebAuthn PRF makes daily access easy without making CardanoWall a seed custodian.
Security
7 min read
Yes, you still need to save your Identity Seed even with a passkey. The passkey is a convenience unlock; the seed is the portable identity that works across CardanoWall, the CLI, SDKs, and any Label 309 tool.
SecurityGuides
8 min read
In the browser, CardanoWall keeps unlocked keys in session memory and writes only encrypted vault ciphertext to IndexedDB — never plaintext Identity Seeds or private keys.
Security
7 min read
Public computer mode stops CardanoWall from writing identity data to the browser, so a shared device keeps no trace after you leave. It does not make a compromised machine safe while you are signed in.
SecurityGuides
7 min read
Synced passkeys roam across your devices; hardware keys stay device-bound and physically controlled. CardanoWall can use either to unlock your identity vault when WebAuthn PRF is supported — and the Identity Seed stays your real backup either way.
Security
7 min read
Removing a passkey re-encrypts your current CardanoWall identity vault to the remaining factors and hard-deletes the old ciphertext — real revocation going forward, but it cannot undo access that already happened.
Security
8 min read
CardanoWall sees account, billing, and public proof data. By design it does not see your plaintext Identity Seed, your private keys, or the plaintext of a sealed file.
Security
8 min read
CardanoWall's address book saves verified contacts so you can seal a record to someone by name instead of pasting a long receive address every time.
Guides
6 min read
Save trusted contacts in CardanoWall — their signing key, receive addresses, a name, and how you verified them — so you can seal a file to the right person without pasting a key under pressure.
Guides
6 min read
A receive address is a public key, not a name. Before you seal a sensitive file, confirm the recipient's address through a trusted channel — encryption can work perfectly and still send to the wrong person.
SecurityGuides
6 min read
Whitelist mode is a per-identity CardanoWall inbox filter that shows records from your trusted contacts first. It does not change the Label 309 record format or block anyone on Cardano.
GuidesSecurity
7 min read
A CardanoWall public profile gives one identity a shareable page with its receive addresses — but a sender should still verify the profile through a trusted channel before sealing a file to it.
Guides
7 min read
A team can share a CardanoWall identity by sharing its Identity Seed — but that hands every holder full signing and decryption power, with no partial or per-person revocation.
GuidesSecurity
8 min read
Deactivating or deleting a CardanoWall identity changes how your account uses it, but it never changes the cryptographic validity of records already published on Cardano.
GuidesSecurity