AmandaRaphael/JWT_study

Security with bcrypt 🔒🔑

This assignment will allow you to play around with the bcrypt package by building a CLI application

What you will be doing

In this assignment you will be expected to write a small authentication function. There is no need to build a server or link to a database; we will be saving our data to the file system.

For this assignment you will have to;

• Use bcrypt to create a hash for a password (register.js), and save that to a file
• Compare a password with the hashed password (login.js)

Tasks

Task 1 - Getting bcrypt

1. Initialise npm with npm init

2. Install the bcrypt npm package

3. Import bcrypt into register.js

Task 2 - Writing a hashing helper function (register.js)

1. Write a function which takes a string as an argument, and uses bcrypt.hash() to hash the result and return the result

   Hint: For now, use 10 as the number of salt rounds

   Hint: This method returns a promise, so you might want to use async / await or use .then()

2. Run your function with the userInput variable, which you can populate from your terminal by including an additional argument, for example: node register.js kittens

3. Test your function by using console.log() to display the output

Task 3 - Playing with salt

Play around with the salt rounds value. Use small and large numbers.

• How long does the program take to run?
• What would an ideal salt rounds number be?

Task 4 - Saving the hashed output to file

We would like to store the hash we generated in the previous function into a file, so we can read it again

1. In the file register.js, import the node.js file system library

   Hint: import { promises as fs } from 'fs'; for the promise version of the library

2. Use the fs.writeFile() method to write the hash to a file

Task 5 - Writing a compare helper function (login.js)

1. Open the file login.js

2. Import bcrypt and the node js file system library (we will use it to read the file)

3. Write a function which takes a string as an argument

4. Use the fs.readFile() method to read the hash you stored in the file you created when you ran register.js

5. Use bcrypt.compare() to compare the userInput variable with the hash from the file you just read

6. bcrypt.compare() returns either true or false

   • If true, display a message to the user stating that the passwords match
   • If false, display a message to the user stating that the passwords do not match

7. Test your code by running node login.js {password} - where {password} is the password you wish to test against the hash