BITCOIN-NATIVE VERIFICATION
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Bitcoin-native.
Agent-to-agent.
Proof21 connects Bitcoin’s public block history with portable evidence, reproducible choices, and policy-based verification across agentic systems.
[Explore the protocol ↗](https://proof21.xyz/docs/)
[The workflow ↓](#evidence-story)
THE BITCOIN FOUNDATION
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Public history.
Independent verification.
Bitcoin supplies a shared reference beyond any one agent or platform: proof-of-work history, reproducible block data, and independently verifiable timestamps.
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Public block history
A common reference for evidence across systems.
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DMT-resolved source material
Registered elements identify reproducible Bitcoin inputs. P21 binds the source, rules and result in portable evidence; no per-proof mint is required.
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Batched commitments
Many evidence digests. One optional Bitcoin timestamp.
[Bitcoin in the protocol ↗](https://proof21.xyz/docs/integrations/bitcoin-stack/)
01 / THE WORKFLOW
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Independent agents.
Verifiable interactions.
Intent. Evidence. Evaluation. Acceptance.
01
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Intent
The initiating agent defines the action, counterparties, constraints, and policy.
02
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Evidence
The executing system returns source records bound to the request.
03
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Evaluation
A verifier evaluates supported claims. Missing evidence remains indeterminate.
04
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Acceptance
The receiving agent applies its policy. A signed decision cannot rewrite verification or settlement.
02 / SHARED PRIMITIVES
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Independent agents.
Shared evidence.
Check actions. Reproduce choices. Carry the evidence.
Check
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Action verification
Agents compare execution evidence against the exact request.
[Explore ↗](https://proof21.xyz/docs/capabilities/check/)
Choice / Sample
Experimental
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Auditable selection
Platforms commit populations and rules before selecting a sample.
[Explore ↗](https://proof21.xyz/docs/capabilities/choice/)
Elements
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Digital matter
Resolve supported DMT definitions against Bitcoin data without minting a token for each receipt. Source element to be announced.
[Explore ↗](https://proof21.xyz/docs/capabilities/elements/)
Verify / Accept
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Policy-aware decisions
Verify the artifact, apply policy, and optionally bind protected actions to an execution gate.
[Explore ↗](https://proof21.xyz/docs/protocol/verification/)
Commit
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Optional anchoring
Bitcoin timestamps anchor evidence without an on-chain write for every action.
[Explore ↗](https://proof21.xyz/docs/capabilities/commit/)
Interoperate
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Portable evidence
Agents exchange verifiable records across platforms and protocols.
[Explore ↗](https://proof21.xyz/integrations/)
03 / ACROSS PLATFORMS
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Connected systems.
Independent policies.
Protocol mappings for agent frameworks, payment rails, and blockchain evidence.
Bitcoin
Binance
Coinbase
MCP
Ethereum
Chainlink
[Explore interoperability ↗](https://proof21.xyz/integrations/)
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NAT community. Open payment choice.
Native NAT and USDC anchor the initial scope. Cross-chain NAT and ecosystem-specific stablecoin rails expand payment choice through individually validated adapters. Receipt verification stays token-free; payment services activate only after settlement testing.
[Explore payment architecture ↗](https://proof21.xyz/docs/integrations/payments/)
04 / RESEARCH
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The ideas behind
the protocol.
Bitcoin, verifiable choices, and evidence between autonomous systems.
[Settlement is not the whole workflow. Read the article ↗](https://proof21.xyz/journal/settlement-is-not-the-workflow/)
[A fair choice starts before the random number. Read the article ↗](https://proof21.xyz/journal/choice-without-rerolls/)
[One artifact. Three different decisions. Read the article ↗](https://proof21.xyz/journal/one-artifact-three-decisions/)
[Read the journal ↗](https://proof21.xyz/journal/)
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Built for agents.
Open to inspection.
Structured resources, complete Markdown, and explicit capability status. No account required to read.
[Agent resources ↗](https://proof21.xyz/agents/)
For developers
[Offline example ↗](https://proof21.xyz/demo/)