merkle-tree-auditor

name	merkle-tree-auditor
description	Audit Merkle tree implementations for second-preimage attacks, leaf-node domain separation, sparse tree edge cases, and proof verification soundness.
allowed-tools	["Read","Grep","Glob","Bash"]

merkle-tree-auditor

Domain auditor for Merkle tree construction and proof verification logic.

When to Use

• Reviewing Merkle inclusion/exclusion proof verification code
• Auditing leaf/internal hashing separation and root construction
• Checking sparse Merkle defaults and update semantics
• Reviewing multi-proof batching and path validation logic

When NOT to Use

• Hash primitive parameter tuning without Merkle tree usage context
• Commitment opening systems not based on Merkle authentication paths
• Marking suspected Merkle issues as confirmed without verification gates

Core Review Areas

1. Second-preimage resistance through strict node typing
2. Leaf-node domain separation and canonical encoding
3. Sparse tree default values and edge-case handling
4. Proof length/path validation and index binding
5. Root update safety and state transition checks

Workflow

Phase 1: Tree model and encoding inventory

• Read references/merkle-checklist.md
• Identify leaf format, node format, and hash domain tags
• Map index-bit ordering and path-direction handling

Phase 2: Proof verification review

• Execute workflows/proof-review.md
• Verify path length/depth checks, left-right ordering, and root comparison
• Check sparse defaults and empty-path handling are fail-closed

Phase 3: Pattern hunt

• Read references/finding-patterns.md
• Prioritize domain-separation gaps, empty-path acceptance, and unbound multiproof reuse

Phase 4: Handoff

• Send surviving findings to crypto-fp-check
• Use zkbugs-index only after verification succeeds

Output Contract

Produce a Merkle-audit handoff that includes:

• The tree variant and proof path under review
• The exact node-typing, path-validation, or root-binding gap
• Whether the issue affects soundness, replay/update integrity, or completeness
• The next verification or reporting route

Reference Index

• references/merkle-checklist.md
• references/finding-patterns.md
• workflows/proof-review.md