nodejs-keccak256

name	nodejs-keccak256
description	Use only when computing Ethereum hashes in JavaScript/TypeScript — Node's sha3-256 is NIST SHA3, not Ethereum Keccak-256, and silently breaks selectors, signatures, and storage slots.

Node.js Keccak-256

Adapted from ECC's nodejs-keccak256 skill (MIT).

Ethereum uses Keccak-256, not the NIST-standardized SHA3 variant exposed by Node's crypto.createHash('sha3-256').

When to Use

• Computing Ethereum function selectors or event topics
• Building EIP-712, signature, Merkle, or storage-slot helpers in JS/TS
• Reviewing any code that hashes Ethereum data with Node crypto directly

See REFERENCE.md for full examples (ethers v6, viem, web3.js, common patterns, address derivation) and codebase audit commands.

Rule

For Ethereum contexts, never use crypto.createHash('sha3-256'). Use Keccak-aware helpers from ethers, viem, web3, or another explicit Keccak implementation.