| # UBDA — Unified Behavioral Data Access (V1.2-alpha) | |
| [](https://github.com/kaymyg/ubda-engine/actions/workflows/ci.yml) | |
| [](LICENSE) | |
| [](Cargo.toml) | |
| UBDA is a prototype **capability-based data access architecture** written in Rust. It | |
| models a system where a software behavioral-trust engine can *influence* trust | |
| levels, but only a separate hardware/TEE-style authority can ever mint the | |
| signed, short-lived capabilities that unlock encryption keys. The goal is to | |
| explore the design pattern — not to ship a production security product. | |
| > ⚠️ **Prototype / educational status.** This is a self-teaching / architecture | |
| > exploration project. `MockHardwareAuthorizer` uses an in-memory Ed25519 | |
| > keypair and a hard-coded demo secret in place of a real HSM/TEE, and Ed25519 | |
| > is used as a placeholder for a future post-quantum signature scheme. Do not | |
| > use this as-is to protect real secrets. | |
| **Try it live:** [UBDA Engine Demo on Hugging Face Spaces](https://huggingface.co/spaces/sahek/ubda-engine) | |
| — click "Run protocol walkthrough" to execute the real compiled engine in your browser. | |
| ## Concept | |
| * **Trust states (`T-1`…`T4`)** describe how strongly the system currently | |
| trusts the requester, moving from a cold, unauthenticated boot through | |
| device authentication, behavioral continuity, step-up (biometric/PIN), and | |
| finally hardware-backed critical elevation. | |
| * **Data classifications (`D0`…`D3`)** describe how sensitive a resource is, | |
| from public system files up to root/master key material. | |
| * Every classification has a **minimum required trust state**. The | |
| `KeyAuthority` refuses to issue a capability if the caller's asserted trust | |
| state doesn't meet it. | |
| * A **Data Access Capability (DAC)** is a signed, time-boxed, single-use, | |
| resource-scoped grant. The `KeyBroker` independently re-verifies the DAC's | |
| signature, expiry, trust-state requirement, operation, and session binding, | |
| and rejects replay via nonce/cap-id tracking, before asking the authority to | |
| derive an ephemeral session key (HKDF-SHA256). | |
| * A hard anomaly signal (or an intrusion interrupt) forces the whole system | |
| into a `Compromised` (`T-1`) state where all key material is invalidated | |
| until an explicit hardware recovery reset. | |
| See [`docs/ARCHITECTURE.md`](docs/ARCHITECTURE.md) for the full state-transition | |
| diagram, component-isolation diagram, and the trust/classification matrix. | |
| ## Project layout | |
| ``` | |
| src/ | |
| types.rs Core enums/structs: TrustState, DataClassification, | |
| DataAccessCapability, telemetry & assertion types | |
| state_machine.rs SystemStateMachine — enforces valid trust transitions | |
| bte_interface.rs BehavioralTrustEngine — turns telemetry into a PolicyAssertion | |
| hardware_authorizer.rs KeyAuthority trait + MockHardwareAuthorizer (Ed25519 + HKDF) | |
| key_broker.rs KeyBroker — verifies & consumes DACs, derives session keys | |
| replay_store.rs Nonce / capability-id replay protection | |
| main.rs End-to-end walkthrough exercising the full protocol | |
| ``` | |
| ## Running it | |
| ```bash | |
| # Run the end-to-end protocol walkthrough | |
| cargo run | |
| # Run the unit test suite (17 tests across state machine, authorizer, broker) | |
| cargo test | |
| ``` | |
| Expected `cargo run` output walks through: reaching T2 via behavioral | |
| continuity, a rejected over-privileged request, a full issue → verify → | |
| derive-key cycle, a blocked replay attempt, a blocked signature-tampering | |
| attempt, full elevation through T3/T4 with real D2/D3 capability issuance, and | |
| a compromise lockout + recovery reset. | |
| ## Requirements | |
| * Rust 2021 edition. Dependency versions in `Cargo.toml` are pinned to remain | |
| buildable on older stable toolchains (tested on rustc 1.75); newer | |
| toolchains work too. | |
| ## License | |
| MIT — see [`LICENSE`](LICENSE). | |
| ## Contributing | |
| Bug reports, feature ideas, and PRs are welcome — see | |
| [`CONTRIBUTING.md`](CONTRIBUTING.md) for setup and the checks CI runs. | |
| ## Security | |
| Found a design or implementation flaw? Please see | |
| [`SECURITY.md`](SECURITY.md) for how to report it responsibly rather than | |
| opening a public issue. | |
| ## Changelog | |
| See [`CHANGELOG.md`](CHANGELOG.md). | |