**Overall Verdict:** Accept — The submission is complete and objectively evaluable, with an independently validated reference circuit meeting both budgets and supporting proof evidence.

**Completeness Check:**

- Instruction: Complete — Deliverables, gate restrictions, bit ordering, budgets, and all six required theorem interfaces are explicit.
- Inputs: Complete — Both tables contain 256 valid byte values, are two-sided inverse permutations, and match the unchanged Lean specification.
- Toolchain: Complete — Lean 4.19.0, a pinned Mathlib revision, and build instructions provide a reproducible open-source workflow.
- Reference output: Complete — Circuit, proof sources, checking instructions, attribution, and build logs are supplied. Independent checks confirm 64 AND gates, 398 total gates, exact outputs, and ordered JSON/Lean data agreement.
- Rubric: Complete — The 20/30/50 allocation clearly distinguishes functional correctness, budget compliance, and complete formal verification, including both circuit inverse identities.

**File and Task Reachability:**

Attachment classification: `reachable`. Inspected `inverse_substitution_inputs.zip`, `inverse_substitution_reference.zip`, and `inverse_substitution_evidence.zip`, including their inventories, specification, tables, circuit data, proof sources, verification scripts, and trial reports. Downloaded sizes match the manifest; archives pass integrity checks and contain no encryption or unsafe member paths. Text is readable UTF-8. Compiled trial executables and Lean artifacts were identified as binary evidence; their internal behavior was not reviewed or trusted.

Task classification: `reachable`. A single-machine workflow can synthesize a circuit, exhaustively compare all 256 outputs, compare JSON and Lean data, and check the required proofs and axiom dependencies. All 256 reference traces independently match circuit execution. Supplied logs report a successful approximately 25-minute proof build with only permitted logical axioms. Lean was unavailable for an independent rebuild, and no uploaded code was executed.

The self-test’s exact but oversized circuit independently reproduces its reported 20/100 outcome; this does not contradict reference feasibility. Solver inputs are separated from reference answers and evaluation evidence.

License keys, accounts, tokens, and other credentials are not required from the contributor. Confidential, proprietary, or internal material may be evaluated as submitted evidence without requiring additional disclosure.

**Special Screening:**

None supported by affirmative evidence. The reference credits public BearSSL components, but that alone does not establish that the constructed target or complete answer is a public benchmark. Independent public-provenance checking was unavailable through approved search.

**Recommended Changes:**

The fixed specification, compliant reference circuit, proof sources, and candid self-test evidence support acceptance. No changes are required.