ethereum-crypto-auditor

name	ethereum-crypto-auditor
description	Audit Rust application code that uses Ethereum cryptography. Use when reviewing secp256k1/ECDSA usage, keccak/EIP-712 hashing, BN254/BLS12-381 precompile interaction, KZG/EIP-4844 patterns, or alloy/ethers-rs API usage.
allowed-tools	["Read","Grep","Glob","Bash"]

ethereum-crypto-auditor

Domain auditor for Ethereum cryptography usage in Rust application code.

When to Use

• Auditing Rust code that calls secp256k1 signing, ecrecover, or ECDSA verification
• Reviewing keccak256 / EIP-712 / EIP-191 hashing in application logic
• Checking BN254 or BLS12-381 precompile input encoding and output decoding
• Auditing KZG blob commitment and opening proof handling (EIP-4844)
• Reviewing alloy / ethers-rs / web3 API usage for type confusion or encoding bugs

When NOT to Use

• Auditing curve arithmetic internals or pairing math (use ecc-pairing-auditor)
• Reviewing ZK circuit constraints or transcript construction
• Declaring findings confirmed without crypto-fp-check

Core Review Areas

1. secp256k1 / ECDSA usage — k-reuse, malleability (high/low-s), recovery ID, ecrecover input encoding
2. Ethereum hash functions — keccak256 vs SHA3-256, EIP-712 / EIP-191 domain separation, prefix handling
3. BN254 / BLS12-381 application usage — precompile input encoding (EIP-196/197, EIP-2537), subgroup membership checks, field element range validation
4. KZG / EIP-4844 usage — trusted setup assumptions, blob commitment encoding, opening proof verification
5. alloy / ethers-rs API misuse — type confusion, encoding errors, signature deserialization, address derivation from wrong public key form
6. EVM precompile interaction — input padding/encoding, output decoding, error handling on failure

Workflow

Phase 1: Checklist pass

• Read references/ethereum-crypto-checklist.md
• Identify all crypto entry points and classify by area
• Enumerate every ECDSA call, hash invocation, precompile interaction, and KZG operation

Phase 2: ECDSA and hash review

• Execute workflows/secp256k1-ecdsa-review.md
• Treat every signature, ecrecover call, and hash-to-address path as hostile until validated
• Verify low-s normalization, recovery ID range, and EIP-712 domain separator construction

Phase 3: Precompile and KZG review

• Execute workflows/evm-precompile-review.md
• Verify input encoding, subgroup membership, field range, and output decoding for every precompile call and KZG operation
• Check error handling on precompile failure and return data length validation

Phase 4: Handoff

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

Output Contract

Produce an Ethereum-crypto handoff that includes:

• The crypto entry points, API calls, and encoding paths involved
• The exact malleability, encoding, domain-separation, or type-confusion issue
• Whether the issue is ECDSA, hash, precompile, KZG, or API-layer
• The next verification or reporting route

Reference Index

• references/ethereum-crypto-checklist.md
• references/finding-patterns.md
• workflows/secp256k1-ecdsa-review.md
• workflows/evm-precompile-review.md