The base protocol for data sharing
The one universal protocol every case builds on: encrypted exchange, addressing, anchoring, verification, and the register.
The Selective Disclosure Exchange Protocol (SDX Protocol) is the base protocol: the one universal layer that every domain protocol and every exchange pattern builds on. It defines how organisations share, address, and verifiably record encrypted data directly with one another: the shape of a record, how parties are addressed, how each field is encrypted, how every exchange is anchored to a shared public audit layer, and how any party reconstructs and verifies state from the recorded log.
It is deliberately minimal. It fixes only what two independent implementations must agree on to interoperate, and nothing more. It does not prescribe what data is shared or with whom: that is the job of the light per-domain taxonomies above it. This overview orients and links; the normative content lives only in the versioned specification.
What the base protocol carries
- The envelope and wire format: a versioned record of typed tiers, encoded deterministically so two implementations compute identical commitments.
- Addressing and discovery: parties and records are addressed over the open overlay standards.
- Encryption: on by default, applied per field, with keys derived on demand rather than stored.
- Anchoring: every exchange is anchored to the public audit layer, a shared, append-only, tamper-evident record no single party controls.
- Verification and replay: state is reconstructed deterministically from the log, and any drift is detectable.
- Identity and delegation: a verifiable chain of scoped, revocable mandates.
- The register: any organisation can publish verifiable claims about itself to a known address for others to look up and verify.
Register and discovery
The register lets any organisation publish verifiable claims about itself, so any counterparty can look those claims up directly and verify their origin and integrity for itself, with no central gatekeeper. It is an application of the base protocol, not a new layer, and its normative rules are in the specification, Section 4.
Specification
The normative core, the conformance rules, the register-and-discovery chapter, and the governance model live in the versioned specification:
What builds on it
- Exchange patterns: reusable configuration templates for using the base protocol.
- Runtime concepts: the narrative reference deep enough to rebuild an interoperable implementation.
- Domain protocols: content authenticity and fraud-signal sharing.
Specification v0.1
A layer-2 taxonomy on the base protocol for comparing patterns and exchanging fraud signals without sharing the underlying data.
Specification v0.1
The normative core of the whole standard: envelope, addressing, encryption, anchoring, verification, identity, the register, conformance, and governance.