Update README.md

Author: learning-zone

README.md

@@ -1404,18 +1404,6 @@ Please note - before pid. This converts a pid to a group of pids for process kil
 
 <br/>
 
-## Q. How can you listen on port 80 with Node?
-
-Instead of running on port 80 we can redirect port 80 to your application\'s port (>1024) using
-
-```bash
-iptables -t nat -I PREROUTING -p tcp --dport 80 -j REDIRECT --to-port 3000
-```
-
-<div align="right">
-    <b><a href="#table-of-contents">↥ back to top</a></b>
-</div>
-
 ## Q. How to use JSON Web Token (JWT) for authentication in Node.js?
 
 JSON Web Token (JWT) is an open standard that defines a compact and self-contained way of securely transmitting information between parties as a JSON object. This information can be verified and trusted because it is digitally signed.
@@ -1425,7 +1413,7 @@ There are some advantages of using JWT for authorization:
 * Purely stateless. No additional server or infra required to store session information.
 * It can be easily shared among services.
 
-JSON Web Tokens consist of three parts separated by dots (.), which are:
+**Syntax:**
 
 ```js
 jwt.sign(payload, secretOrPrivateKey, [options, callback])
@@ -1501,128 +1489,6 @@ The `jwt.sign()` method takes a payload and the secret key defined in `config.js
     <b><a href="#table-of-contents">↥ back to top</a></b>
 </div>
 
-## Q. How to implement asymmetric cryptography when signing and verify JSON Web Token (JWT) for authentication in Node.js?
-
-JSON Web Token (JWT) is an open standard that defines a compact and self-contained way of securely transmitting information between parties as a JSON object. This information can be verified and trusted because it is digitally signed.
-
-There are some advantages of using JWT for authorization:
-
-- Purely stateless. No additional server or infra required to store session information.
-- It can be easily shared among services.
-
-**Syntax:**
-
-```js
-jwt.sign(payload, secretOrPrivateKey, [options, callback]);
-```
-
-**1. Header** - Consists of two parts: the type of token (i.e., JWT) and the signing algorithm (i.e., HS512)
-
-**2. Payload** - Contains the claims that provide information about a user who has been authenticated along with other information such as token expiration time.
-
-**3. Signature** - Final part of a token that wraps in the encoded header and payload, along with the algorithm and a secret
-
-**Installation:**
-
-```bash
-npm install jsonwebtoken bcryptjs --save
-```
-
-**Usage:**
-
-1. `mkdir certs` then run `cd certs`
-
-**Inside the certs folder generate public and private key pairs:**
-
-```bash
-// Private Key
->> openssl genrsa -out accessTokenPrivatekey.pem 4096
-
-// Public Key
->> openssl rsa -pubout -in accessTokenPrivatekey.pem -out accessTokenPublickey.pem
-```
-
-**Example**:
-
-```js
-/**
- * AuthController.js
- */
-const express = require('express');
-const router = express.Router();
-const bodyParser = require('body-parser');
-const { readFileSync } = require('fs');
-const User = require('../user/User');
-
-const jwt = require('jsonwebtoken');
-const bcrypt = require('bcryptjs');
-const config = require('../config');
-
-router.use(bodyParser.urlencoded({ extended: false }));
-router.use(bodyParser.json());
-
-router.post('/register', function (req, res) {
-  const hashedPassword = bcrypt.hashSync(req.body.password, 8);
-
-  User.create(
-    {
-      name: req.body.name,
-      email: req.body.email,
-      password: hashedPassword,
-    },
-    (err, user) => {
-      if (err) {
-         return res.status(500).send('There was a problem registering the user.');
-      }
-
-      // Using the fs module get the private key of the accesstoken you created.
-      const ACCESS_TOKEN_PRIV_KEY = readFileSync(
-        './certs/accessTokenPrivateKey.pem',
-        'utf8'
-      );
-
-      // Create an access token using the private key pair, and specify the algorithm you will use.
-      const token = jwt.sign({ id: user._id }, ACCESS_TOKEN_PRIV_KEY, {
-        algorithm: 'RS256',
-        expiresIn: 86400, // expires in 24 hours
-      });
-      res.status(200).send({ auth: true, token: token });
-    }
-  );
-});
-```
-
-**To verify a token use the public key:**
-
-```js
-const ACCESS_TOKEN_PUB_KEY = readFileSync(
-  './certs/accessTokenPubliKey.pem',
-  'utf-8'
-);
-
-/** Use the Access token Public Key to verify the JWT access token */
-jwt.verify(
-  token,
-  ACCESS_TOKEN_PUB_KEY,
-  { algorithms: ['RS256'] },
-  (err, user) => {
-    console.log(err);
-    if (err) res.status(403);
-    console.log(user);
-  }
-);
-```
-
-The `jwt.sign()` method takes a payload, private key defined in `./certs/accessTokenPrivateKey.pem` and an object which contains other information about the token, this includes the algorithm `{ algorithm: 'RS256'}`. It creates a unique string of characters representing the payload.
-
-**Reference:**
-
-* *[https://www.npmjs.com/package/jsonwebtoken](https://www.npmjs.com/package/jsonwebtoken)*
-
-<div align="right">
-    <b><a href="#table-of-contents">↥ back to top</a></b>
-</div>
-
 ## Q. How to build a microservices architecture with Node.js?
 
 Microservices are a style of **Service Oriented Architecture (SOA)** where the app is structured on an assembly of interconnected services. With microservices, the application architecture is built with lightweight protocols. The services are finely seeded in the architecture. Microservices disintegrate the app into smaller services and enable improved modularity.