The importance of security in web applications cannot be understated. In this article, we'll explore two popular methods for securing TypeScript applications: JSON Web Tokens (JWT) and bcrypt. We'll see how to use each of these technologies to secure a TypeScript application, and we'll also learn about some of the potential pitfalls associated with each approach.
JSON Web Token (JWT) is a popular way to securely transmit data between two parties. JWT is composed of three parts:
One common use case for JWT is to transmit information about an authenticated user between a web application and a backend server. For example, when a user logs in to a web application, a JWT can be used to transmit information about the user (such as the user's name and email address) to the backend server. The backend server can then use this information to generate a response that is tailored to the user.
Another common use case for JWT is to transmit information about a user's session from a web application to a backend server. This is often done in order to avoid having to store sensitive information (such as a user's session ID) in a cookie. When a user's session expires, the JWT can be used to invalidate the user's session on the backend server.
Bcrypt is a password hashing function that is designed to be computationally expensive to compute. This is important because it makes it difficult for an attacker to brute force a password.
Bcrypt is typically used in conjunction with a salt. A salt is a randomly generated string that is used to make the password hashing function more difficult to compute. The salt is typically stored alongside the hashed password.
The most common way to use JWT in a TypeScript application is to use the jsonwebtoken package. This package provides a set of helper functions that make it easy to generate and verify JWT.
To use jsonwebtoken, we first need to install it:
npm install jsonwebtoken
Once jsonwebtoken is installed, we can use it to generate a JWT:
const jwt = require('jsonwebtoken');
const payload = {
userId: 123,
email: 'user@example.com',
name: 'John Doe',
};
const secret = 'secret';
const token = jwt.sign(payload, secret);
The jwt.sign()
function takes two arguments: the payload and the secret. The payload is the data that we want to encode in the JWT, and the secret is used to generate the JWT signature.
Once we have generated the JWT, we can transmit it to the backend server. The backend server can then use the jwt.verify()
function to verify the JWT:
const jwt = require('jsonwebtoken');
const token = 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VySWQiOjEyMywiZW1haWwiOiJ1c2VyQGV4YW1wbGUuY29tIiwibmFtZSI6IkpvaG4gRG9lIn0.S30gaSmqhzPZU6mxPiwm53cH-j2dhYfBYuYTR3LsyiE';
const secret = 'secret';
const payload = jwt.verify(token, secret);
The jwt.verify()
function takes two arguments: the token and the secret. The token is the JWT that we want to verify, and the secret is used to verify the JWT signature.
If the JWT is valid, the jwt.verify()
function will return the decoded payload. If the JWT is invalid, the jwt.verify()
function will throw an error.
The most common way to use bcrypt in a TypeScript application is to use the bcryptjs package. This package provides a set of helper functions that make it easy to generate and verify bcrypt hashes.
To use bcryptjs, we first need to install it:
npm install bcryptjs
Once bcryptjs is installed, we can use it to hash a password:
const bcrypt = require('bcryptjs');
const password = 'secret';
const salt = bcrypt.genSaltSync(10);
const hash = bcrypt.hashSync(password, salt);
The bcrypt.hashSync()
function takes two arguments: the password and the salt. The password is the password that we want to hash, and the salt is used to make the password hashing function more difficult to compute.
Once we have generated the hash, we can transmit it to the backend server. The backend server can then use the bcrypt.compareSync()
function to compare the hash with the password:
const bcrypt = require('bcryptjs');
const password = 'secret';
const hash = '$2a$10$2znyB6.qE1T.1S7X3C5NU.7bHJNz5KUzHJZzM6DQLN8tm4Gxe6Ay';
bcrypt.compareSync(password, hash); // true
The bcrypt.compareSync()
function takes two arguments: the password and the hash. The password is the password that we want to compare, and the hash is the bcrypt hash that we want to compare it with.
If the password is valid, the bcrypt.compareSync()
function will return true
. If the password is invalid, the bcrypt.compareSync()
function will return false
.
One potential pitfall associated with JWT is that the data in the payload is not encrypted. This means that if an attacker manages to obtain the JWT, they will be able to view the data in the payload.
Another potential pitfall associated with JWT is that the secret used to generate the JWT signature must be kept secret. If the secret is compromised, an attacker will be able to generate their own JWT with any data that they choose.
One potential pitfall associated with bcrypt is that it is a one-way hashing function. This means that once a password has been hashed, it cannot be reversed. This can make it difficult to recover a password if it is forgotten.
Another potential pitfall associated with bcrypt is that it is computationally expensive to compute. This can make it difficult to use bcrypt on large datasets.