mrwulf
4140ff3249
Gen merge: extract.sh now co-extracts the Scalar52 backend and the public scalar::from_bytes_mod_order[_wide] conversions into the SAME CurveField model, so the whole library — field, curve_models, edwards, scalar — shares one type universe (Scalar is a single structure, not two). The scalar proof chain repoints by one import line (ScalarDenote: CurveScalar.Funs -> CurveField.Funs); check-scalar.sh's gen list follows. Both buttons — the scalar certificates and the field/group/dsm certificates — pass fresh over the merged gen, so the merge is proven-safe, not merely hoped-safe. Verify glue (gen/CurveSig): the extracted ed25519-dalek verify_sha512 path, integrated against the proven model: - TypesExternal.lean imports CurveField.Types, so CompressedEdwardsY / EdwardsPoint / Scalar in the glue ARE the proven model's types. Only the genuinely foreign types stay opaque: sha2.Sha512, ed25519.Signature, signature.error.Error. - FunsExternal.lean imports CurveField.Funs, so every curve/scalar call (compress, vartime_double_scalar_mul_basepoint, as_bytes, neg, from_bytes_mod_order[_wide]) resolves to a proven definition — no axioms. The `?`-operator plumbing (Try::branch, FromResidual::from_residual) and compressed_from_bytes get real definitions. Only the SHA-512 hasher (sha512_new/update/finalize_bytes) and two opaque wire accessors (Signature.to_bytes, Error.new) remain axiomatized — the deliberate, documented hash-oracle boundary. Audited: `verify_sha512`'s entire axiom cone is [propext, Classical.choice, Quot.sound, sha2.Sha512, sha512_new, sha512_update, sha512_finalize_bytes, ed25519.Signature.to_bytes, signature.error.Error.new] — zero curve axioms, zero scalar axioms. The verify path is definitionally grounded in the certified model; the only trust boundary is SHA-512. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> |
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|---|---|---|
| verification | ||
| .gitignore | ||
| README.md | ||
| TRUSTED-BASE.md | ||
dalek-ed25519-verified
Formal verification of the ed25519 implementation in dalek-cryptography/curve25519-dalek (upstream, v5.0.0-rc.1), 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 |
✅ proven | [propext, Classical.choice, Quot.sound] |
| Group law (Edwards) | edwardsImplementation |
✅ proven | [propext, Classical.choice, Quot.sound] |
| Scalar mod ℓ | scalarImplementation (add ✅ sub ✅ mul ✅) |
✅ proven | [propext, Classical.choice, Quot.sound] |
| Signature (EdDSA) | verifyEquation (planned) |
⏳ planned | — |
Status legend: ✅ proven & axiom-audited · ⏳ in progress · ❌ not started.
This table is updated only when verification/check.sh passes for the layer.
Source
- Upstream: dalek-cryptography/curve25519-dalek, commit
4cf8db2 - Pinned/patched source: saymrwulf/curve25519-dalek-source, commit
135ed70 - Patches: minimal Aeneas-compatibility only (documented in the source repo)
- Verified backend:
backend/serial/u64(FieldElement51,Scalar52). SIMD/AVX backends are out of scope (marked opaque).
Toolchain (pinned)
| Component | Version |
|---|---|
| Aeneas | bf13c42e |
| Charon | 9dd7f23c |
| Lean | v4.30.0-rc2 |
| OCaml | 5.3.0 |
Reproducing
source ~/aeneas-toolchain/env.sh
cd verification
./extract.sh # Rust → LLBC → Lean (regenerates gen/)
./check.sh # compiles EVERY shipped file + axiom-audits EVERY certificate
The scalar layer has its own pair of buttons:
./extract-scalar.sh # regenerates gen/CurveScalar (Scalar52 limb arithmetic)
./check-scalar.sh # compiles the scalar gen + all scalar proofs (add, sub,
# Montgomery mul) and kernel-audits 10 certificates,
# including the scalarImplementation aggregate
Trusted base
See 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).
Provenance
Proof engineering in this repository builds on the verification methodology and proof architecture of PlanetMacro/ed25519-verificationtest (the reference solution). All proofs here are checked against this fork's own extracted code; nothing is claimed that the check script does not compile.