bcx
bcx is the Rust crate for Bifrost Casual Exchange: a no-std-first
protocol foundation for verifiable causal accountability across network
operations.
BCX is not an HTTP replacement. It defines signed operation facts, causal parentage, admission decisions, effect receipts, bounded WHY queries, and selective-disclosure explanation bundles. HTTP/3 can carry BCX objects for compatibility, while high-assurance deployments can later use a native BCX application protocol over QUIC.
Current Status
bcx is at repository foundation stage. The crate is not production-ready.
Implemented now:
no_stddefault build.- zero third-party runtime dependencies.
- root publishable crate named
bcx. - focused no-std subcrates for core IDs, model types, crypto envelope metadata, policy profiles, and wire limits.
- local check script, modularity guard, release metadata guard, and GitHub CI.
- implementation, version, threat-model, toolchain, and modularity docs.
Trust Dashboard
| Area | Status |
|---|---|
| License | EUPL-1.2 |
| MSRV | Rust 1.90.0 |
| Preferred toolchain | Rust 1.96.0 |
| Default target | no_std |
| Runtime dependencies | zero third-party crates |
| Unsafe policy | unsafe_code = "forbid" |
| Main crate | bcx |
| First serious target | 1.0.0 production-ready protocol crate |
| High-security position | trust canonical signed BCX objects, not an HTTP wrapper |
Rust Version Support
The minimum supported Rust version is Rust 1.90.0. New deployments should
prefer the latest stable Rust validated by the project.
Compatibility evidence:
| Rust | Local Evidence |
|---|---|
1.90.0 |
planned full check gate |
1.91.0 |
planned cargo check --all-features |
1.92.0 |
planned cargo check --all-features |
1.93.0 |
planned cargo check --all-features |
1.94.0 |
planned cargo check --all-features |
1.95.0 |
planned cargo check --all-features |
1.96.0 |
current pinned toolchain |
Workspace Shape
| Crate | Purpose |
|---|---|
bcx |
Published facade crate and stable user entry point. |
bcx-core |
Identifiers, nonces, replay sequence primitives, validation errors. |
bcx-model |
Cause, action, decision, effect, truth, and assurance model types. |
bcx-crypto |
Crypto-agile signature envelope metadata and verifier traits. |
bcx-policy |
Protocol profiles, proof levels, and disclosure levels. |
bcx-wire |
Wire version and bounded-message limit primitives. |
Future transport crates should stay separate from the core crate so bcx
remains no-std by default.
Verification
Run the local gate:
The gate checks formatting, tests, no-default-feature builds, all-feature builds, clippy, docs, package metadata, file-size policy, release metadata, and installed target triples.
Security Position
BCX must distinguish:
- what was observed,
- what was declared,
- what was cryptographically verified,
- what policy enforced,
- what another participant acknowledged,
- what remains unknown.
The protocol must not claim to prove a participant's internal motive. A signed purpose is an attributable declaration, not proof that the declared purpose was truthful.
Read Security Policy, Threat Model, and Implementation Plan before using BCX in any security-sensitive system.