Formally verified ed25519 (anza-xyz solana-ed25519): field + complete Edwards addition law proven in Lean 4 via Charon/Aeneas; axiom-audited certificates
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mrwulf 214a4cd3d6 THE SIGNATURE APEX on the anza fork: verify_accepts_iff, button-enforced
FOURTH AND FINAL PYRAMID CAPPED - the signature layer is complete on all
four ed25519 forks. anza's verify code lives in the same crate as the
curve (solana-ed25519), so the whole verify path joins the merged
CurveField extraction directly: one universe, no glue layer, no FQ-name
welding, and the Error enum plus the parse/filter helpers are all real
extracted code.

- extract.sh: verify_sha512 start-from joins the merged stanza;
  sha512_hash3 and the foreign ed25519 crate opaque; RUSTFLAGS
  --cfg curve25519_serial_only pins the serial backend so
  get_selected_backend extracts as the real constant Serial (the stale
  dispatch axiom is deleted from FunsExternal).
- gen/CurveField externals: real defs for the ?-operator plumbing
  (Try::branch, FromResidual) and faithful identity models for
  Choice::unwrap_u8 (transparent-u8 body: self.0) and the RangeFull
  get_unchecked[_mut] raw-pointer pair (Rust body returns the pointer
  unchanged) - the three would-be cone intruders, eliminated.
- Proofs/SigApexSpec.lean: verify_loop_full (standard three-axiom cone)
  and verify_accepts_iff - the verifier accepts IFF the recomputed
  compress([k](-A) + [s]B) equals the signature's R byte-for-byte, with
  the ZIP-215 legacy filters and the s < l parse conditioned by
  hypotheses, mirroring the siblings' hparse.
- check.sh Phase 3b enforces the apex cone to be EXACTLY
  [propext, Classical.choice, Quot.sound, ed25519.Signature,
   ed_sigs.sha512_hash3, ed25519.Signature.r_bytes,
   ed25519.Signature.s_bytes]
  - the tightest boundary of the four pyramids: the SHA-512 oracle plus
  the foreign wire-format type and its two byte accessors, nothing else.

check.sh (incl. Phase 3b) + check-scalar.sh both green.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-04 23:48:08 +02:00
verification THE SIGNATURE APEX on the anza fork: verify_accepts_iff, button-enforced 2026-07-04 23:48:08 +02:00
.gitignore skeleton: proof-pyramid layout, honest status table, trusted-base doc 2026-07-02 13:10:26 +02:00
README.md Scalar layer complete: Montgomery reduction + full mul ported, scalarImplementation aggregate 2026-07-03 21:36:35 +02:00
TRUSTED-BASE.md skeleton: proof-pyramid layout, honest status table, trusted-base doc 2026-07-02 13:10:26 +02:00

anza-ed25519-verified

Formal verification of the ed25519 implementation in anza-xyz/cryptography (Solana, solana-ed25519 crate), 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      │   Scalar52 ops correct mod 
        ├──────────────────────────────┤
        │  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 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: anza-xyz/cryptography, commit 0a54cca
  • Pinned/patched source: saymrwulf/anza-cryptography-source, commit 77043ab
  • Patches: minimal Aeneas-compatibility only (documented in the source repo)
  • Closest relative of the reference solution (same crate layout as solana-ed25519).

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 + the proven scalar foundation

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).