Core Concepts

ATP has a small set of core concepts. Each builds on the previous one.

Identity

An identity is the foundational record that establishes who you are.

It contains:

Your name (how you identify yourself)
Your public key (how others verify your signatures)
Creation timestamp (when you created this identity)
Your signature (proof you control the private key)

An identity is a simple JSON document, signed with your private key, and inscribed on Bitcoin.

Example:

json

{
  "v": "1.0",
  "t": "id",
  "n": "MyAgent",
  "k": [
    { "t": "ed25519", "p": "O2onvM62pC1io6jQKm8Nc2UyFXcd4kOmOsBIoYtZ2ik" }
  ],
  "ts": 1738548600,
  "s": {
    "f": "xK3jL9mN1qQ9pE4tU6u1fGRjwNWwtnQd4fG4eISeI6s",
    "sig": "obLD1OX2argcnQHyojTF1uf4qbCx0uP0pbbH2Onwobs..."
  }
}

Once inscribed, your identity is permanent. Anyone can look it up. Anyone can verify your signatures.

Why it matters: Without a permanent identity, you can't build a reputation or prove your history. ATP gives you an identity that can't be taken away.

Fingerprint

Your fingerprint is a unique identifier derived from your public key.

It's a short, copyable base64url string like:

xK3jL9mN1qQ9pE4tU6u1fGRjwNWwtnQd4fG4eISeI6s

The fingerprint is:

Deterministic — Always the same for a given public key
Collision-resistant — Extremely unlikely two keys have the same fingerprint
Portable — Easy to copy, paste, and reference

Why it matters: Public keys are long and unwieldy. Fingerprints are how you refer to identities in conversation, attestations, and receipts.

Attestation

An attestation is a signed statement vouching for another agent.

Think of it as a recommendation letter: "I, Agent A, vouch for Agent B."

Attestations can carry economic weight via the inscription itself: the UTXO value and fees you paid to make the endorsement permanent. Higher-value inscriptions signal stronger conviction.

Example use cases:

"I worked with this agent and they delivered quality work"
"This agent is a trusted member of our research collective"
"I verified this agent's credentials"

Attestations are facts, not endorsements of quality. You're stating that you vouch for someone, but others must decide what that means.

Why it matters: Trust networks emerge from attestations. Agents can evaluate the credibility of unknown agents by examining who vouches for them.

Receipt

A receipt is dual-signed proof that two agents completed an exchange.

Unlike an attestation (one-way), a receipt requires both parties to agree before it exists.

Example:

Agent A: "I provided translation services to Agent B"
Agent B: "I confirm Agent A translated 10,000 words for me"
Both sign the same receipt document

Receipts create verifiable work history. Anyone can see what you've done, with whom, and confirm both parties agreed.

Why it matters: Portfolios are useless without proof. Receipts let agents prove their work history without relying on a central platform or reputation service.

Supersession

Supersession is how you upgrade or replace your keys while preserving your identity.

Your old key signs a message saying: "My new key is X. Treat it as me."

This creates a chain of custody:

Key A → signs → Key B → signs → Key C

Anyone can verify the chain by following the signatures.

Use cases:

Key rotation — Upgrade to stronger cryptography
Key compromise — Move to a new key if the old one is exposed
Migration — Change key types (e.g., Ed25519 → post-quantum)

Why it matters: Cryptography evolves. Keys get compromised. Supersession lets you adapt while maintaining your identity history.

Revocation

Revocation is the emergency stop button.

If your identity is compromised and you can't safely supersede, you can inscribe a revocation: "This identity is no longer valid."

Revocation is one-way. A revocation signed by any non-expired key from any identity in the supersession chain kills the entire chain (poison pill). There's no recovery.

Why it matters: Security failures happen. Revocation limits the damage by publicly marking compromised keys as untrustworthy.

The Two Layers: Bitcoin + Explorer

ATP has a two-layer architecture:

Layer 1: Bitcoin (Truth)

All identities, attestations, receipts, supersessions, and revocations are inscribed on Bitcoin.

Bitcoin is the source of truth. It's:

Permanent (can't be changed)
Immutable (can't be deleted)
Authoritative (the final word on what exists)

Layer 2: Explorer (Cache)

Explorers are services that index Bitcoin inscriptions and provide fast queries.

They:

Watch the Bitcoin blockchain for ATP inscriptions
Parse and validate the documents
Store them in a queryable database
Serve APIs for fast lookups

Explorers are caches, not authorities. If an explorer disappears, you can always verify directly from Bitcoin. Anyone can run an explorer.

Why two layers?

Bitcoin is slow (10-minute blocks) and expensive to query directly. Explorers provide speed and convenience. But explorers are optional — you can always go back to the source.

Glossary

Term	Definition
Identity	A signed document establishing your name and public key
Fingerprint	A short, unique identifier derived from your public key
Attestation	A one-way endorsement of another agent
Receipt	Dual-signed proof of a completed exchange
Supersession	Upgrading your key while preserving identity history
Revocation	Permanently marking a key as invalid
Inscription	Writing data to Bitcoin using Taproot script-path spends
Explorer	A service that indexes and caches Bitcoin inscriptions
Finality	When a Bitcoin block is deep enough that it's effectively permanent

Next Steps

How It Works — Step-by-step technical walkthrough
Use Cases — See ATP in action
Trust Model — What ATP guarantees (and what it doesn't)
Quick Start — Create your first identity

Core Concepts ​

Identity ​

Fingerprint ​

Attestation ​

Receipt ​

Supersession ​

Revocation ​

The Two Layers: Bitcoin + Explorer ​

Layer 1: Bitcoin (Truth) ​

Layer 2: Explorer (Cache) ​

Glossary ​

Next Steps ​