mrwulf
195eafcc16
- `Proofs/DsmNafLoadSpec.lean` (generated) — the byte-to-word LE load of
`non_adjacent_form`: four 8-peel inner walks (t |= bytes[8k+bi] << 8bi)
and the outer 4-peel filling x_u64[0..3]; x_u64[4] stays 0 (the pad word
the cross-word window reads at positions >= 251).
- `Proofs/DsmNafMath.lean` — the pure arithmetic of the w=5 digit loop:
`nafSum`/`nafSum_set`; window-read lemmas `naf_window_single` /
`naf_window_cross` (cross-word disjoint-OR read sees (V >> pos) mod 32);
invariant steps `naf_even_step` / `naf_odd_step` (Nat.mod_mul telescope:
digit + promoted carry reconstruct the consumed bits EXACTLY, in ZZ);
carry-kill `naf_carry_even` / `naf_carry_odd` (V < 2^253 forces the
carry dead before bit 256); `naf_exit` (nafSum naf 256 = V exactly).
The digit-loop walk (stage 3) composes these next; its invariant is
nafSum naf 256 + carry*2^pos = V mod 2^pos
with digits at k >= pos all zero and carry = 1 -> pos <= 254.
CERTS += naf_load_spec, naf_window_cross, naf_exit (axiom-clean).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
|
||
|---|---|---|
| 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).