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https://github.com/saymrwulf/dalek-ed25519-verified.git
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mrwulf
c4fbd063bd
extract-scalar.sh: function-level roots (add/sub/mul/square/montgomery_*) yield a 28-def Scalar52 limb-arithmetic gen with ZERO iterator/byte/wrapper entanglement — the byte-serialization and high-level Scalar wrapper (which pull untranslatable chunks/zip iterators) are excluded by scoping, not faked. Proofs/ScalarDenote.lean (compiles, axiom-clean): Ell = ℓ = 2^252+..., the Scalar52 denotation ⟦·⟧ : Scalar52 → ZMod ℓ, the ScBnd 52-bit limb invariant, and L_val — the transpiled constants::L denotes EXACTLY the group order ℓ (kernel-checked, no native_decide). add/sub (Range-loop conditional reductions, tractable — field-layer pattern) and the Montgomery mul path (shares pasta's big-coefficient kernel limit) are in progress. check-scalar.sh is green for the foundation. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
65 lines
3.2 KiB
Markdown
65 lines
3.2 KiB
Markdown
# dalek-ed25519-verified
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Formal verification of the ed25519 implementation in **dalek-cryptography/curve25519-dalek (upstream, v5.0.0-rc.1)**, built as a
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coherent proof pyramid in Lean 4 via the Charon/Aeneas transpilation pipeline:
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```
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┌──────────────────────────────┐
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│ Signature (EdDSA verify) │ accepted ⇒ [8][S]B = [8]R + [8][k]A
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├──────────────────────────────┤
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│ Scalar arithmetic mod ℓ │ Scalar52 ops correct mod ℓ
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├──────────────────────────────┤
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│ Group law (twisted Edwards) │ point ops = complete addition law
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├──────────────────────────────┤
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│ Field 𝔽_p, p = 2²⁵⁵ − 19 │ FieldElement51 ops correct mod p
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└──────────────────────────────┘
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```
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Every layer states its theorems about the **actual Aeneas-transpiled Rust
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code** (never about a hand-written re-model), and every claim in the status
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table below is backed by a compiled proof plus an axiom audit of the named
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certificate. Files that do not compile under `verification/check.sh` are not
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in this repository.
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## Layer status
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| Layer | Certificate | Status | Axioms of certificate |
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|-------|-------------|--------|-----------------------|
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| Field 𝔽_p | `fieldImplementation` | ✅ proven | `[propext, Classical.choice, Quot.sound]` |
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| Group law (Edwards) | `edwardsImplementation` | ✅ proven | `[propext, Classical.choice, Quot.sound]` |
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| Scalar mod ℓ | `scalarImplementation` | 🔨 foundation | denotation + L=ℓ proven; add/sub/mul in progress |
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| Signature (EdDSA) | `verifyEquation` | ⏳ in progress | — |
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Status legend: ✅ proven & axiom-audited · ⏳ in progress · ❌ not started.
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This table is updated only when `verification/check.sh` passes for the layer.
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## Source
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- **Upstream**: [dalek-cryptography/curve25519-dalek](https://github.com/dalek-cryptography/curve25519-dalek), commit `4cf8db2`
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- **Pinned/patched source**: [saymrwulf/curve25519-dalek-source](https://github.com/saymrwulf/curve25519-dalek-source), commit `135ed70`
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- **Patches**: minimal Aeneas-compatibility only (documented in the source repo)
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- Verified backend: `backend/serial/u64` (`FieldElement51`, `Scalar52`). SIMD/AVX backends are out of scope (marked opaque).
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## Toolchain (pinned)
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| Component | Version |
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|-----------|---------|
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| Aeneas | `bf13c42e` |
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| Charon | `9dd7f23c` |
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| Lean | `v4.30.0-rc2` |
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| OCaml | `5.3.0` |
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## Reproducing
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```bash
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source ~/aeneas-toolchain/env.sh
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cd verification
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./extract.sh # Rust → LLBC → Lean (regenerates gen/)
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./check.sh # compiles EVERY shipped file + axiom-audits EVERY certificate
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```
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## Trusted base
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See [TRUSTED-BASE.md](TRUSTED-BASE.md) for the complete list of assumptions
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(Lean kernel, mathlib, Charon/Aeneas semantics, external-function models,
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and — in the signature layer only — an opaque SHA-512 model).
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