generate public private key pair (RSA RS256) for use with koa-jwt jasonwebtoken etc.

jwtRS256.sh

# generate private key
openssl genrsa -out jwtRS256.key 2048
# extatract public key from it
openssl rsa -in jwtRS256.key -pubout > jwtRS256.key.pub

testkeys.js

const jwt2 = require('jsonwebtoken');
const fs = require("fs")
const public_key = fs.readFileSync('jwtRS256.key.pub');
const private_key = fs.readFileSync('jwtRS256.key');

var token=jwt2.sign({"user":"me"},private_key, { algorithm: 'RS256'})
var res = jwt2.verify(token, public_key, { algorithm: 'RS256'})
console.log(res)