agent-action-capsule (Rust)

Reference verification for the Agent Action Capsule, the Rust sibling of the Python reference and the Go and TypeScript implementations in action-state-group/agent-action-capsule. It is checked against the same conformance vectors, and CI verifies Python-, Go-, TypeScript- and Rust-sealed capsules in every implementation.

use agent_action_capsule::verify::{decode_capsule_json, verify};

let capsule = decode_capsule_json(bytes)?;
let result = verify(&capsule, None);
if result.ok {
    println!("{}", result.capsule_id.unwrap_or_default());
}

Decode capsules with decode_capsule_json, a strict RFC 8259 decoder. Numbers are kept as written (serde_json's arbitrary_precision feature), so a float or an out-of-range integer is reported by check 1 instead of being rounded away. serde_json::from_slice is not a substitute: with that feature it turns an object holding serde_json's private number token into a number, which changes the Capsule ID. Cargo unifies features, so arbitrary_precision applies to every serde_json user in a build that depends on this crate.

The bundle feature adds checkpointed-local-log, which also carries an HTTP witness client; record verification does not need it.

The strict feature (which includes bundle) adds bundle::verify_bundle_strict, the checks a verifier needs before it tells a person that a Bundle is VALID: each record's producer signature, the checkpoint read only from its signed COSE form, producer-selected Bundles, the disclosures overlay as one claim, and the witness receipts in checkpoint.witnesses under a witness directory the caller supplies (none is trusted by default). Its result carries a VALID, INCOMPLETE or INVALID verdict; the plain verify_bundle is unchanged. It adds scitt-cose-receipt, coset and p256. vectors/bundle/strict/README.md describes every rule.

use agent_action_capsule::bundle::{verify_bundle_strict, StrictOptions};

let result = verify_bundle_strict(&bundle, &StrictOptions {
    require_signature: true,
    witness_directory: Some(&directory),
});
println!("{}", result.verdict());

The settlement feature adds settlement::verify_settlements, which derives payment and delivery states from both parties' leg records.

Not yet in Rust: Disclosure Envelopes, composed bundles, and the emitter and presentation layers.

Development

From rust/:

cargo fmt --check
cargo clippy --locked --all-targets --all-features -- -D warnings
cargo test --locked --all-features

The tests read ../../vectors/, ../../provenance-mode-vectors/ and ../../spec/REGISTRY.md. data/REGISTRY.md and data/cpb_provisional.json are byte copies of spec/REGISTRY.md and python/agent_action_capsule/data/cpb_provisional.json; the drift test fails until a changed source is copied over.

Licensed under BSD-3-Clause.