bcrypt

What is bcrypt?

The bcrypt npm package is a library for hashing and comparing passwords securely in Node.js. It implements the bcrypt password-hashing function, which is designed to build a cryptographic hash of a user's password. Bcrypt is widely used due to its security features and resistance to brute-force attacks.

What are bcrypt's main functionalities?

Hashing Passwords

This feature allows you to securely hash a plaintext password. The 'saltRounds' parameter defines the cost factor for the hashing process, which determines the amount of time required to calculate a single bcrypt hash.

const bcrypt = require('bcrypt');
const saltRounds = 10;
const myPlaintextPassword = 's0/\/\P4$$w0rD';

bcrypt.hash(myPlaintextPassword, saltRounds, function(err, hash) {
  // Store hash in your password DB.
});

Comparing Passwords

This feature is used to compare a plaintext password against a previously hashed one to check if they match. It is commonly used during the login process to validate user credentials.

const bcrypt = require('bcrypt');
const myPlaintextPassword = 's0/\/\P4$$w0rD';
const someOtherPlaintextPassword = 'not_bacon';
const hash = '$2b$10$N9qo8uLOickgx2ZMRZoMyeIjZAgcfl7p92ldGxad68LJZdL17lhWy';

bcrypt.compare(myPlaintextPassword, hash, function(err, result) {
  // result == true
});

bcrypt.compare(someOtherPlaintextPassword, hash, function(err, result) {
  // result == false
});

Other packages similar to bcrypt

argon2

Argon2 is another password hashing library that won the Password Hashing Competition and is recommended for new applications. It is considered to be more resistant to GPU cracking attacks compared to bcrypt.

scrypt

Scrypt is a password-based key derivation function that is designed to be costly in both time and memory, making it hard to perform large-scale custom hardware attacks. It is similar to bcrypt but with a focus on memory-intensiveness.

pbkdf2

PBKDF2 (Password-Based Key Derivation Function 2) is part of RSA Laboratories' Public-Key Cryptography Standards (PKCS) series, and it's widely used for password hashing. It's not as secure as bcrypt for password storage because it's more vulnerable to GPU attacks.

README

bcrypt-node

Lib to help you hash passwords.
bcrypt on wikipedia

Catalyst: How To Safely Store A Password

Dependencies

• NodeJS
• OpenSSL

From NPM

npm install bcrypt

From Source

Assuming you've already built node, you can run the waf script:
node-waf configure node-waf build npm link

Usage - Sync

To hash a password:
var bcrypt = require('bcrypt');
var salt = bcrypt.gen_salt_sync(10);
var hash = bcrypt.encrypt_sync("B4c0//", salt);

To check a password:
var bcrypt = require('bcrypt');
var salt = bcrypt.gen_salt_sync(10);
var hash = bcrypt.encrypt_sync("B4c0//", salt); bcrypt.compare_sync("B4c0//", hash); // true
bcrypt.compare_sync("not_bacon", hash); // false

Usage - Async

To hash a password:
var bcrypt = require('bcrypt');
bcrypt.gen_salt(10, function(err, salt) { bcrypt.encrypt("B4c0//", salt, function(err, hash) { //something }); });

To check a password:
var bcrypt = require('bcrypt'); bcrypt.gen_salt(10, function(err, salt) { bcrypt.encrypt("B4c0//", salt, function(err, hash) { bcrypt.compare("B4c0//", hash, function(err, res) { // res == true
}); bcrypt.compare("not_bacon", hash, function(err, res) { // res = false }); }); });

API

• BCrypt
  • gen_salt_sync(rounds, seed_length)
    • rounds - [OPTIONAL] - the number of rounds to process the data for. (default - 10)
    • seed_length - [OPTIONAL] - RAND_bytes wants a length. to make that a bit flexible, you can specify a seed_length. (default - 20)
  • gen_salt(rounds, seed_length, cb)
    • rounds - [OPTIONAL] - the number of rounds to process the data for. (default - 10)
    • seed_length - [OPTIONAL] - RAND_bytes wants a length. to make that a bit flexible, you can specify a seed_length. (default - 20)
    • cb - [REQUIRED] - a callback to be fired once the salt has been generated. uses eio making it asynchronous.
  • encrypt_sync(data, salt)
    • data - [REQUIRED] - the data to be encrypted.
    • salt - [REQUIRED] - the salt to be used in encryption.
  • encrypt(data, salt, cb)
    • data - [REQUIRED] - the data to be encrypted.
    • salt - [REQUIRED] - the salt to be used in encryption.
    • cb - [REQUIRED] - a callback to be fired once the data has been encrypted. uses eio making it asynchronous.
  • compare_sync(data, encrypted)
    • data - [REQUIRED] - data to compare.
    • encrypted - [REQUIRED] - data to be compared to.
  • compare(data, encrypted, cb)
    • data - [REQUIRED] - data to compare.
    • encrypted - [REQUIRED] - data to be compared to.
    • cb - [REQUIRED] - a callback to be fired once the data has been compared. uses eio making it asynchronous.

Hash Info

The characters that comprise passwords are ./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789$.

Testing

I am using nodeunit. I like the way you write tests with it and I like the default output. As such you'll need it to run the tests. I suspect my tests would run on an older version, but these were written and worked against 0.5.1 npm install nodeunit@0.5.1 nodeunit test/

Credits

The code for this comes from a few sources:

• blowfish.cc - OpenBSD
• bcrypt.cc - OpenBSD
• bcrypt::gen_salt - gen_salt inclusion to bcrypt
• bcrypt_node.cc - me

Contributors

Antonio Salazar Cardozo

License

Unless stated elsewhere, file headers or otherwise, the license as stated in the LICENSE file.