¥ECDSA key pairs
const { subtle } = require('node:crypto').webcrypto;
async function generateEcKey(namedCurve = 'P-521') {
  const {
    publicKey,
    privateKey
  } = await subtle.generateKey({
    name: 'ECDSA',
    namedCurve,
  }, true, ['sign', 'verify']);
  return { publicKey, privateKey };
}