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2 commits

Author SHA1 Message Date
dee1554d8e Merge scalar into CurveField: one type universe, serial-only backend
Replicates dalek's gen merge: extract.sh co-extracts the Scalar52 backend
and scalar::from_bytes_mod_order[_wide] into the CurveField model, pins
RUSTFLAGS --cfg curve25519_dalek_backend="serial" (SIMD dispatch compiles
out; get_selected_backend becomes a real definition), and upgrades
unwrap_u8 to the documented Choice-model definition. ScalarDenote repoints
by one import line; both buttons green over the merged gen.

Prepares the verify-glue integration (CurveSig) on this fork.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-04 22:20:26 +02:00
9541d3bf7a Add scalar-layer foundation (Scalar52 arithmetic mod ℓ)
Transpile the Scalar52 limb backend (backend::serial::u64::scalar
add/sub/mul/square/montgomery_*) from Rust to Lean via Charon/Aeneas,
scoped at the function level to the iterator-free arithmetic core.

  - verification/extract-scalar.sh: function-level Charon/Aeneas extraction
  - verification/gen/CurveScalar/{Types,Funs}.lean: transpiled model (27 defs).
    This fork (v4.1.2) implements Scalar52::sub's constant-time conditional add
    with a pure arithmetic mask (constants::L[i] & underflow_mask), so the
    extraction pulls in NO external functions or types (unlike v5 dalek, which
    routes sub through subtle, and v4.1.3, which uses a local black_box).
  - verification/gen/CurveScalar/{TypesExternal,FunsExternal}.lean: decl-free
    stub modules kept so the check manifest is uniform across forks.
  - verification/Proofs/ScalarDenote.lean: semantic foundation — Scalar52
    denotation into ℤ/ℓℤ, limb-bound invariant, and L_val (the transpiled
    constants::L denotes exactly the group order ℓ, kernel-checked).
  - verification/check-scalar.sh: guarded compile of the gen modules plus the
    denotation foundation.

check-scalar.sh passes: gen compiles; denotation + L = ℓ proven.
add/sub/mul remain in progress.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-02 21:27:33 +02:00