code: function getPubKeyFromPriKey(priKeyBytes) {
    var ec = new EC('secp256k1');
    var key = ec.keyFromPrivate(priKeyBytes, 'bytes');
    var pubkey = key.getPublic();
    var x = pubkey.x;
    var y = pubkey.y;
    var xHex = x.toString('hex');
    while (xHex.length < 64) {
      xHex = "0" + xHex;
    }
    var yHex = y.toString('hex');
    while (yHex.length < 64) {
      yHex = "0" + yHex;
    }
    var pubkeyHex = "04" + xHex + yHex;
    var pubkeyBytes = hexStr2byteArray(pubkeyHex);
    return pubkeyBytes;
  }
docs: return pubkey by 65 bytes, priKeyBytes is byte[]