Understanding bcrypt for User Authentication

Introduction bcrypt is a library to help you hash passwords.

In the context of storing password, hashes are better to store than plain text passwords. Even if an attacker gains access to the database, they won’t be able to reverse-engineer the original password from the hash.

Using bcrypt in User Registration

In a typical user registration process, we need to hash the password provided by the user before storing it in the database. Here’s how you can do it using bcrypt:

const bcrypt = require('bcrypt')

// Generate a salt
const salt = await bcrypt.genSalt(10)

// Hash the password with the salt
const hashedPassword = await bcrypt.hash(password, salt)

In this code snippet, bcrypt.genSalt is used to generate a salt.

A salt is random data that is used as an additional input to a one-way function that hashes data, a password in this case.

The bcrypt.hash function is then used to hash the user’s password along with the salt.

Hashing is the process of converting an input of any length into a fixed size string of text, using a mathematical function.

Using bcrypt in User Login

When a user tries to login, we need to verify their password. Here’s how you can do it using bcrypt:

const passwordCorrect = user === null
  ? false
  : await bcrypt.compare(password, user.passwordHash)

In this code snippet, bcrypt.compare is used to compare the password provided by the user with the hashed password stored in the database. If the two passwords match, bcrypt.compare returns true.

Conclusion

bcrypt is a powerful tool for securing user passwords in your applications. By using bcrypt, you can ensure that your user’s passwords are stored securely and that even if your data is compromised, the passwords of your users will remain secure.