01
User boundary
Application ↔ wallet
Apps state intent. Wallets protect keys, permissions, transaction construction, and user-owned state.
Architecture at a glance
One stack.
Replaceable parts.
The point of an open interface is not sameness. Each layer can have many implementations while the boundaries stay stable enough for the ecosystem to compound.
Application intentBitcoin verification
02
Peer boundary
Identity, messages & payments
Relationship keys, selective identity, mutual authentication, private payloads, and peer payments.
03
Application state
Overlay admission & lookup
Protocol-specific rules decide what belongs; lookup services make the resulting state useful.
04
Verification substrate
Transactions & SPV proofs
Portable transaction graphs and Merkle paths let every higher layer validate without one trusted database.
Why the layers matter
Architecture rules
These are the strategic constraints that make the standards useful as an ecosystem rather than a pile of documents.
Keys stay at the wallet boundary.
Applications request outcomes and scoped cryptographic operations; they do not become wallets by accident.
Peers prove what they need.
Relationship-specific keys and selectively revealed certificates reduce correlation and excess disclosure.
Protocols own admission rules.
Overlays can compete on operations and query performance while agreeing on what makes an output valid.
Proof travels with the transaction.
Portable SPV material reduces hidden dependence on a single indexer, API, or wallet vendor.