const crypto = require('crypto');

const { privateKey, publicKey } = crypto.generateKeyPairSync('ec', {
  namedCurve: 'sect239k1'
});

const sign = crypto.createSign('SHA256');
sign.write('some data to sign');
sign.end();
const signature = sign.sign(privateKey, 'hex');

const verify = crypto.createVerify('SHA256');
verify.write('some data to sign');
verify.end();
console.log(verify.verify(publicKey, signature));
// Prints: true or false

>> node sign.js
internal/crypto/keygen.js:73
    throw new ERR_INVALID_OPT_VALUE('publicKeyEncoding', publicKeyEncoding);
    ^

TypeError [ERR_INVALID_OPT_VALUE]: The value "undefined" is invalid for option "publicKeyEncoding"
    at parseKeyEncoding (internal/crypto/keygen.js:73:11)
    at check (internal/crypto/keygen.js:240:7)
    at Object.generateKeyPairSync (internal/crypto/keygen.js:53:16)
    at Object.<anonymous> (/Users/norfeldt/Desktop/AsymEnc/sign.js:3:42)
    at Module._compile (internal/modules/cjs/loader.js:689:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:700:10)
    at Module.load (internal/modules/cjs/loader.js:599:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:538:12)
    at Function.Module._load (internal/modules/cjs/loader.js:530:3)
    at Function.Module.runMain (internal/modules/cjs/loader.js:742:12)