commit b85945f72f75851b680956f36288fcd366b6dcf7 Author: mrwulf Date: Thu Jul 2 13:10:26 2026 +0200 skeleton: proof-pyramid layout, honest status table, trusted-base doc Co-Authored-By: Claude Fable 5 diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..24f9b74 --- /dev/null +++ b/.gitignore @@ -0,0 +1,3 @@ +*.olean +.lake/ +lake-manifest.json diff --git a/README.md b/README.md new file mode 100644 index 0000000..9cc5f19 --- /dev/null +++ b/README.md @@ -0,0 +1,65 @@ +# betrusted-ed25519-verified + +Formal verification of the ed25519 implementation in **betrusted-io/curve25519-dalek (Precursor/Xous fork, v4.1.2)**, built as a +coherent proof pyramid in Lean 4 via the Charon/Aeneas transpilation pipeline: + +``` + ┌──────────────────────────────┐ + │ Signature (EdDSA verify) │ accepted ⇒ [8][S]B = [8]R + [8][k]A + ├──────────────────────────────┤ + │ Scalar arithmetic mod ℓ │ Scalar52 ops correct mod ℓ + ├──────────────────────────────┤ + │ Group law (twisted Edwards) │ point ops = complete addition law + ├──────────────────────────────┤ + │ Field 𝔽_p, p = 2²⁵⁵ − 19 │ FieldElement51 ops correct mod p + └──────────────────────────────┘ +``` + +Every layer states its theorems about the **actual Aeneas-transpiled Rust +code** (never about a hand-written re-model), and every claim in the status +table below is backed by a compiled proof plus an axiom audit of the named +certificate. Files that do not compile under `verification/check.sh` are not +in this repository. + +## Layer status + +| Layer | Certificate | Status | Axioms of certificate | +|-------|-------------|--------|-----------------------| +| Field 𝔽_p | `fieldImplementation` | ⏳ in progress | — | +| Group law (Edwards) | `edwardsImplementation` | ⏳ in progress | — | +| Scalar mod ℓ | `scalarImplementation` | ⏳ in progress | — | +| Signature (EdDSA) | `verifyEquation` | ⏳ in progress | — | + +Status legend: ✅ proven & axiom-audited · ⏳ in progress · ❌ not started. +This table is updated only when `verification/check.sh` passes for the layer. + +## Source + +- **Upstream**: [betrusted-io/curve25519-dalek](https://github.com/betrusted-io/curve25519-dalek), commit `16e087a` +- **Pinned/patched source**: [saymrwulf/betrusted-curve25519-dalek-source](https://github.com/saymrwulf/betrusted-curve25519-dalek-source), commit `64ee8f0` +- **Patches**: minimal Aeneas-compatibility only (documented in the source repo) +- **Scope caveat**: this verifies the fork's pure-Rust `serial/u64` path. The Engine25519 hardware-accelerator path on Precursor is different code and is NOT covered by these proofs. + +## Toolchain (pinned) + +| Component | Version | +|-----------|---------| +| Aeneas | `bf13c42e` | +| Charon | `9dd7f23c` | +| Lean | `v4.30.0-rc2` | +| OCaml | `5.3.0` | + +## Reproducing + +```bash +source ~/aeneas-toolchain/env.sh +cd verification +./extract.sh # Rust → LLBC → Lean (regenerates gen/) +./check.sh # compiles EVERY shipped file + axiom-audits EVERY certificate +``` + +## Trusted base + +See [TRUSTED-BASE.md](TRUSTED-BASE.md) for the complete list of assumptions +(Lean kernel, mathlib, Charon/Aeneas semantics, external-function models, +and — in the signature layer only — an opaque SHA-512 model). diff --git a/TRUSTED-BASE.md b/TRUSTED-BASE.md new file mode 100644 index 0000000..960a17b --- /dev/null +++ b/TRUSTED-BASE.md @@ -0,0 +1,25 @@ +# Trusted base + +What you must believe for the theorems in this repository to transfer to the +running Rust code. Everything else is machine-checked. + +1. **Lean 4 kernel** (v4.30.0-rc2) and its three foundational axioms + `[propext, Classical.choice, Quot.sound]`. Every certificate is + `#print axioms`-audited against exactly this list. +2. **mathlib** (prebuilt oleans fetched by `lake exe cache get`). +3. **Charon + Aeneas** (pinned `9dd7f23c` / `bf13c42e`): the translation + from Rust MIR to the Lean model is assumed faithful. The generated + `gen/` files are never edited (comments only); proofs are stated ABOUT them. +4. **External-function models** (`gen/*/FunsExternal.lean`): Rust items that + Aeneas cannot translate (constant-time `subtle` primitives, iterator + plumbing, formatting) are axiomatized as opaque symbols. The axiom audit + proves none of these axioms enters the dependency cone of any certificate, + except where a model is explicitly listed below. +5. **SHA-512 (signature layer only)**: the hash is modeled as an opaque + function ℬ* → ℬ⁶⁴ with no algebraic properties assumed. The signature + certificate has the shape "IF the hash model computes SHA-512, THEN an + accepted signature satisfies the EdDSA verification equation". The hash + implementation itself is NOT verified. +6. **Compilation of Rust to machine code** (rustc backend) is out of scope, + as is side-channel behaviour (timing, speculation). The proofs are about + functional correctness at the MIR/LLBC level.