freeCodeCamp/curriculum/challenges/english/06-information-security-and-quality-assurance/information-security-with-helmetjs/understand-bcrypt-hashes.english.md

---
id: 58a25bcef9fc0f352b528e7c
title: Understand BCrypt Hashes
challengeType: 2
---

## Description
<section id='description'>
As a reminder, this project is being built upon the following starter project on <a href='https://glitch.com/#!/import/github/freeCodeCamp/boilerplate-bcrypt/'>Glitch</a>, or cloned from <a href='https://github.com/freeCodeCamp/boilerplate-bcrypt/'>GitHub</a>.
BCrypt hashes are very secure. A hash is basically a fingerprint of the original data- always unique. This is accomplished by feeding the original data into a algorithm and having returned a fixed length result. To further complicate this process and make it more secure, you can also <em>salt</em> your hash. Salting your hash involves adding random data to the original data before the hashing process which makes it even harder to crack the hash.
BCrypt hashes will always looks like <code>$2a$13$ZyprE5MRw2Q3WpNOGZWGbeG7ADUre1Q8QO.uUUtcbqloU0yvzavOm</code> which does have a structure. The first small bit of data <code>$2a</code> is defining what kind of hash algorithm was used. The next portion <code>$13</code> defines the <em>cost</em>. Cost is about how much power it takes to compute the hash. It is on a logarithmic scale of 2^cost and determines how many times the data is put through the hashing algorithm. For example, at a cost of 10 you are able to hash 10 passwords a second on an average computer, however at a cost of 15 it takes 3 seconds per hash... and to take it further, at a cost of 31 it would takes multiple days to complete a hash. A cost of 12 is considered very secure at this time. The last portion of your hash <code>$ZyprE5MRw2Q3WpNOGZWGbeG7ADUre1Q8QO.uUUtcbqloU0yvzavOm</code>, looks like 1 large string of numbers, periods, and letters but it is actually 2 separate pieces of information. The first 22 characters is the salt in plain text, and the rest is the hashed password!
<hr>To begin using BCrypt, add it as a dependency in your project and require it as 'bcrypt' in your server.
Submit your page when you think you've got it right.
</section>

## Instructions
<section id='instructions'>

</section>

## Tests
<section id='tests'>

```yml
tests:
  - text: BCyrpt is a dependency
    testString: getUserInput => $.get(getUserInput('url')+ '/_api/package.json') .then(data => { var packJson = JSON.parse(data); assert.property(packJson.dependencies, 'bcrypt', 'Your project should list "bcrypt" as a dependency'); }, xhr => { throw new Error(xhr.statusText); })
  - text: BCrypt has been properly required
    testString: getUserInput => $.get(getUserInput('url')+ '/_api/server.js').then(data => {assert.match(data, /bcrypt.*=.*require.*('|")bcrypt('|")/gi, 'You should correctly require and instantiate socket.io as io.');}, xhr => { throw new Error(xhr.statusText); })

```

</section>

## Challenge Seed
<section id='challengeSeed'>

</section>

## Solution
<section id='solution'>

```js
// solution required
```
</section>