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
Posts in “Guides”
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
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
How to Receive a Sealed Record
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: 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
10 min read
How to Use CardanoWall Without the Website
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
Why Publishing a Proof Costs Money
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
8 min read
Creative Proofs for Artists
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
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
9 min read
Publish Your First Proof of Existence on Cardano
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
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
7 min read
Why the Identity Seed Still Matters When You Have a Passkey
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
7 min read
Public Computer Mode: Using CardanoWall on a Shared Device
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
8 min read
How the CardanoWall Address Book Works
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
Create Your CardanoWall Address Book
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
Verify a Recipient Before You Seal a File
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: Focus Your Inbox on Trusted Senders
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
Public Profiles and Receive Addresses on CardanoWall
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
Shared Team Identities: One Identity, Many People
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
Active, Deactivated, Deleted: What Each Identity State Means
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