Prevent Ethereum hashing bugs in JavaScript and TypeScript. Node's sha3-256 is NIST SHA3, not Ethereum Keccak-256, and silently breaks selectors, signatures, storage slots, and address derivation. Use when hashing for Ethereum in JavaScript or TypeScript, or when a selector, signature, storage slot, or derived address is wrong.
Install
npx skills add affaan-m/ECC --skill nodejs-keccak256npx skills add affaan-m/ECC --skill nodejs-keccak256 -a claude-code -gnpx skills add affaan-m/ECC --skill nodejs-keccak256 -a codex -ggemini skills install https://github.com/affaan-m/ECC.git --path skills/nodejs-keccak256gh skill install affaan-m/ECC nodejs-keccak256git clone --depth 1 https://github.com/affaan-m/ECC /tmp/affaan-m__ECC
mkdir -p ~/.claude/skills ~/.agents/skills
cp -R /tmp/affaan-m__ECC/skills/nodejs-keccak256 ~/.claude/skills/nodejs-keccak256 # Claude Code
cp -R /tmp/affaan-m__ECC/skills/nodejs-keccak256 ~/.agents/skills/nodejs-keccak256 # Codex, Cursor, Gemini CLI, Copilot, OpenCode