Why bcryptjs used?

Bcryptjs is a JavaScript library that implements the Bcrypt password hashing algorithm, which is used to securely store passwords in Node.js applications: 

Here's an overview of its key methods and properties along with examples:
const bcrypt = require('bcryptjs');
const plaintextPassword = 'mysecretpassword';

bcrypt.hash(plaintextPassword, 10, (err, hash) => {
    if (err) {
        console.error('Error while hashing:', err);
    } else {
        console.log('Hashed password:', hash);
        // Store `hash` in database for user
    }
});

1. Bcryptjs is a secure
2. Bcryptjs used industry-standard method for storing passwords
3. Its have less susceptible to dictionary-based cyberattacks. 

You can adjust salt rounds based on your server's capabilities. If performance is critical, start with a lower number, like 8, and gradually increase it as your system's performance improves. Monitor the hash time and user experience to find an optimal balance.

Yes, BcryptJS is suitable for modern applications due to its strong security features and adaptability. Its resistance to common attacks makes it a reliable choice for password hashing. Additionally, it integrates easily with Node.js applications, ensuring secure user authentication practices.

Common pitfalls include using too low salt rounds, which makes passwords vulnerable, or failing to handle errors properly in asynchronous operations. Additionally, avoid hardcoding sensitive data like passwords or salts, and ensure that you always store the hash securely after hashing.

Install BcryptJS using npm with the command `npm install bcryptjs`. After installation, require it in your code: `const bcrypt = require('bcryptjs');`. This enables you to start hashing and comparing passwords in your application.

BcryptJS produces a string output that includes the algorithm identifier, cost factor, salt, and hash, formatted as `$2a$<cost>$<salt>$<hash>`. This format allows the library to extract the parameters during verification, ensuring consistent hash comparisons for security.

While BcryptJS is designed for password hashing, it can technically hash any data. However, it's optimized for passwords, and other hashing algorithms like SHA-256 may be more appropriate for data integrity checks or non-sensitive information due to performance considerations.

Hashing is a one-way function that transforms data into a fixed-size string, making it irreversible, while encryption is reversible, allowing the original data to be retrieved with a key. BcryptJS uses hashing to securely store passwords, ensuring they cannot be easily decrypted.

A rainbow table attack involves using precomputed tables of hash values to quickly find plaintext passwords. BcryptJS mitigates this risk through its unique salting process, ensuring that even identical passwords produce different hashes, making rainbow tables ineffective against BcryptJS hashes.

BcryptJS prevents brute force attacks by using adaptive hashing with configurable salt rounds, which increases the time it takes to compute a hash. This makes it more computationally expensive for attackers to try multiple passwords, enhancing overall security against such attacks.