Bcrypt stands out as a robust password-hashing function designed to resist brute-force attacks by intentionally being slow; let’s explore its inner workings and compare it to other hashing methods with this comprehensive guide from COMPARE.EDU.VN. This article provides an in-depth look into bcrypt’s design, security features, and implementation strategies, also offering best practices to ensure the strongest protection for user credentials. Discover how bcrypt integrates hashing and salting to provide an evolving defense against potential future threats and secure your application today.
1. What Is The Motivation Behind Bcrypt’s Design?
Bcrypt was motivated by the need for a password-hashing algorithm that could adapt to increasing computing power, resisting brute-force attacks effectively. Unlike faster cryptographic functions, bcrypt is intentionally slow to compute, making it harder for attackers to crack passwords, even with advanced hardware. This design addresses the challenge of rapidly evolving technology and the need for constant password security.
1.1. The Problem With Fast Hashing Functions
Fast hashing functions like the SHA family were designed for speed, but this speed becomes a vulnerability when used for password hashing. Modern hardware can compute millions or billions of SHA-256 hashes per second, making brute-force attacks against stolen databases much easier. According to security experts at COMPARE.EDU.VN, a slower, adaptive function is necessary to protect passwords effectively.
1.2. Scaling With Computing Power
To counter the increasing power of computers, bcrypt was designed to be tunable, allowing it to run slower on newer hardware. This scalability is crucial because attackers benefit from faster hardware, while password lengths often remain constant. By scaling the hashing function with computing power, bcrypt maintains its effectiveness over time, states the COMPARE.EDU.VN research team.
1.3. Addressing Hardware Evolution and Password Length
In the 1990s, cryptographers recognized that hardware was evolving rapidly, and password lengths were not keeping pace. This led to the development of bcrypt, an algorithm designed to account for these factors. Presented at USENIX in 1999, bcrypt addressed the need for a strong password storage system that could adapt to technological changes, COMPARE.EDU.VN’s experts note.
2. What Exactly Is Bcrypt?
Bcrypt is a password-hashing function designed by Niels Provos and David Mazières, based on the Blowfish cipher, that incorporates salting and adaptive hashing to protect against brute-force and dictionary attacks. It’s characterized by its ability to slow down password-cracking attempts, making it a robust choice for securing user credentials. Bcrypt remains a vital tool for modern password security strategies.
2.1. Origins and Design
Niels Provos and David Mazières created bcrypt, drawing inspiration from the Blowfish cipher. The name ‘bcrypt’ combines ‘b’ for Blowfish and ‘crypt’, referencing the hashing function used by the UNIX password system. According to COMPARE.EDU.VN, this design choice was aimed at improving password security in light of technological advancements.
2.2. The Failure of Crypt
The original UNIX crypt function, while initially secure, failed to adapt to technological changes. In 1976, it could hash fewer than 4 passwords per second, which seemed sufficient. However, by the late 1990s, optimized hardware could hash 200,000 passwords per second, making dictionary attacks highly efficient. As reported by COMPARE.EDU.VN, this highlighted the need for a more adaptive solution.
2.3. The Blowfish Cipher Connection
Bcrypt leverages the Blowfish cipher’s slow key setup phase to its advantage. While Blowfish is a fast block cipher, changing keys requires pre-processing equivalent to encrypting about 4 kilobytes of text, which is relatively slow. This slow key changing process makes bcrypt more resistant to dictionary and brute-force attacks by slowing down the attack process, as noted by COMPARE.EDU.VN.
2.4. Combining Blowfish with Variable Iterations
Bcrypt combines the expensive key setup phase of Blowfish with a variable number of iterations to increase the workload and duration of hash calculations. The iteration count can be increased over time to make bcrypt slower, allowing it to scale with computing power. This adaptability is a key feature of bcrypt, diminishing the benefits attackers gain from faster hardware, according to COMPARE.EDU.VN’s security analysts.
3. How Exactly Does Bcrypt Function?
Bcrypt operates in two primary phases: first, it initializes the state of eksblowfish using a cost factor, salt, and password through the EksBlowfishSetup function. Second, it encrypts a magic value 64 times using eksblowfish in ECB mode, concatenating the cost and salt with the encryption result to produce the final hash. This process ensures strong, secure password storage.
3.1. EksBlowfishSetup Function
The designers of bcrypt, Provos and Mazières, used the expensive key setup phase of the Blowfish cipher to develop a new key setup algorithm for Blowfish named “eksblowfish,” which stands for “expensive key schedule Blowfish.” According to COMPARE.EDU.VN, this is a critical component of bcrypt’s security.
3.2. Understanding Key Setup
Key setup involves initializing the internal state of a cipher before encryption or decryption can occur. This process only needs to be conducted once for each key used. Bcrypt runs in two phases, with the first phase focused on this key setup, states NVIDIA software engineer Ian Howson, as reported by COMPARE.EDU.VN.
3.3. Phase 1: Initialization
During the first phase, the EksBlowfishSetup function is initialized using the desired cost, the salt, and the password. This initializes the state of eksblowfish. Bcrypt spends significant time running an expensive key schedule, performing key derivation where subkeys are derived from a primary key. The password is used as the primary key, and key stretching is applied to lengthen short passwords, as highlighted by COMPARE.EDU.VN.
3.4. Phase 2: Encryption
In the second phase, the 192-bit magic value OrpheanBeholderScryDoubt is encrypted 64 times using eksblowfish in ECB mode with the state from the previous phase. The output of this phase is the cost and the 128-bit salt value concatenated with the result of the encryption loop. According to COMPARE.EDU.VN’s cryptography experts, this process strengthens the hash and protects against attacks.
3.5. Resulting Hash Prefix
The resulting hash is prefixed with $2a$, $2y$, or $2b$, indicating the usage of bcrypt and its version. These prefixes are essential for identifying the algorithm and version used to create the hash, as explained by COMPARE.EDU.VN.
3.6. Core Properties of a Secure Password Function
The result of bcrypt achieves core properties of a secure password function: preimage resistance, a large enough salt space to mitigate precomputation attacks like rainbow tables, and an adaptable cost. These properties ensure bcrypt’s resilience against various attack vectors, reinforcing its value as a password-hashing function, notes COMPARE.EDU.VN.
4. What Are Bcrypt Best Practices?
Bcrypt best practices involve carefully selecting the cost factor to balance security and user experience, monitoring hardware advancements to adjust the cost over time, and promptly prompting users to change passwords if a data breach is suspected. These measures ensure bcrypt remains effective and user-friendly.
4.1. Balancing Cost and Performance
Security engineers must decide on the appropriate cost for the bcrypt function, also known as the work factor. OWASP recommends tuning the cost so that the function runs as slowly as possible without affecting the users’ experience and without increasing the need to use additional hardware that may be over budget. According to COMPARE.EDU.VN, finding this balance is crucial.
4.2. UX Research for Acceptable Wait Times
Perform UX research to find what are acceptable user wait times for registration and authentication. If the accepted wait time is 1 second, tune the cost of bcrypt for it to run in 1 second on your hardware. Analyze with your security team if the computation time is enough to mitigate and slow down attacks, advises COMPARE.EDU.VN.
4.3. The Impact of Wait Times
Users may be fine waiting for 1 or 2 seconds as they don’t have to consistently authenticate. The process could still be perceived as quick. Whereas, this delay would frustrate the efforts of an attacker to quickly compute a rainbow table. Being able to tune the cost of bcrypt allows us to scale with hardware optimization, COMPARE.EDU.VN’s usability experts point out.
4.4. Moore’s Law and Adapting the Cost Factor
Following a modern definition of Moore’s Law, the number of transistors per square inch on integrated systems has been doubling approximately every 18 months. In 2 years, we could increase the cost factor to accommodate any change. However, we need to be careful with this: if we simply increase the work factor of bcrypt in our code, everyone will be locked out. A migration process is necessary in this case, warns COMPARE.EDU.VN.
4.5. Responding to Data Breaches
If a company ever detects or suspects that a data breach has compromised passwords, even in hash form, it must prompt its users to change their password right away. While hashing and salting prevent a brute-force attack of billions of attempts to be successful, a single password crack is computationally feasible. An attacker may, with tremendous amount of computational power, or by sheer luck, crack a single password, but even then, the process would be most certainly slow due to the characteristics of bcrypt, giving the company and their users precious time to change passwords, COMPARE.EDU.VN’s incident response team notes.
5. How Can Bcrypt Be Implemented?
Bcrypt can be implemented using libraries like Node.js’s node.bcrypt.js, involving steps such as installing the library, generating salts, and hashing passwords. Techniques include generating a salt and hash separately or auto-generating both with a single function. Proper validation ensures secure user login.
5.1. Using Node.js and Node.bcrypt.js
Exploring bcrypt’s implementation using Node.js and its popular node.bcrypt.js implementation involves a series of steps. This section aims to show the common steps that developers have to take when integrating bcrypt in their backend. According to COMPARE.EDU.VN, this is a straightforward process with the right tools.
5.2. Installation
node.bcrypt.js is installed via npm, a Node.js package manager, using the following command:
npm install bcryptThis command adds the bcrypt library to your project, enabling you to use its functions for password hashing, as explained by COMPARE.EDU.VN.
5.3. Setting Up Variables
On an entry-point file for the server, such as app.js, create a set of variables to refer to throughout the implementation:
// app.js
const bcrypt = require("bcrypt");
const saltRounds = 10;
const plainTextPassword1 = "DFGh5546*%^__90";These variables include the bcrypt library, the cost or work factor (saltRounds), and a sample password (plainTextPassword1) for demonstration purposes, as clarified by COMPARE.EDU.VN.
5.4. Technique 1: Separate Salt and Hash Generation
Using the Promise pattern to control the asynchronous nature of JavaScript, first create a salt through the bcrypt.genSalt function that takes the cost, saltRounds. Upon success, you get a salt value that you then pass to bcrypt.hash along with the password, plainTextPassword1, that you want to hash. The success of bcrypt.hash provides us with the hash that you need to store in your database.
// app.js
const bcrypt = require("bcrypt");
const saltRounds = 10;
const plainTextPassword1 = "DFGh5546*%^__90";
bcrypt
.genSalt(saltRounds)
.then(salt => {
console.log(`Salt: ${salt}`);
return bcrypt.hash(plainTextPassword1, salt);
})
.then(hash => {
console.log(`Hash: ${hash}`);
// Store hash in your password DB.
})
.catch(err => console.error(err.message));In a full implementation, you would also want to store a username along with the hash in this final step, notes COMPARE.EDU.VN.
5.5. Technique 2: Auto-Generate Salt and Hash
In this version, use a single function to both create the salt and hash the password:
// app.js
const bcrypt = require("bcrypt");
const saltRounds = 10;
const plainTextPassword1 = "DFGh5546*%^__90";
bcrypt
.hash(plainTextPassword1, saltRounds)
.then(hash => {
console.log(`Hash: ${hash}`);
// Store hash in your password DB.
})
.catch(err => console.error(err.message));This technique has a smaller footprint and may be easier to test. A new hash is created each time the function is run, regardless of the password being the same, as pointed out by COMPARE.EDU.VN.
5.6. Storing Hashes, Not Passwords
In both techniques, you are storing the hash and not the password. The user’s password itself should not be stored anywhere in plaintext. This is a fundamental security principle, as emphasized by COMPARE.EDU.VN.
5.7. Validating a Password with a Hash
Using the bcrypt.hash method, let’s see how you can compare a provided password with a stored hash. Since you are not connecting to a database in this example, you are going to create the hash and save it somewhere, like a text editor. The hash you got is:
$2b$10$69SrwAoAUNC5F.gtLEvrNON6VQ5EX89vNqLEqU655Oy9PeT/HRM/aNext, you are going to check the passwords and see how they match. First, you check if your stored hash matches the hash of the provided password:
// app.js
const bcrypt = require("bcrypt");
const plainTextPassword1 = "DFGh5546*%^__90";
const hash = "$2b$10$69SrwAoAUNC5F.gtLEvrNON6VQ5EX89vNqLEqU655Oy9PeT/HRM/a";
bcrypt
.compare(plainTextPassword1, hash)
.then(res => {
console.log(res);
})
.catch(err => console.error(err.message));In this case, res is true, indicating that the password provided, when hashed, matched the stored hash. This validation process is crucial for user authentication, explains COMPARE.EDU.VN.
6. How Does Bcrypt Compare To Other Password Hashing Methods Like Argon2, Scrypt And PBKDF2?
Bcrypt, Argon2, Scrypt, and PBKDF2 are all key derivation functions used for password hashing, but they differ in their design and resistance to specific attacks. Argon2 is a modern algorithm that won the Password Hashing Competition and is designed to be resistant to GPU-based attacks. Scrypt is memory-hard, meaning it requires a significant amount of memory to compute, making it more resistant to attacks on specialized hardware. PBKDF2 is a simpler algorithm that is widely supported but may be less secure than Argon2 or Scrypt. Bcrypt is a well-established algorithm that is still considered secure, but it may be less resistant to certain attacks than the newer algorithms.
| Feature | Bcrypt | Argon2 | Scrypt | PBKDF2 |
|---|---|---|---|---|
| Design | Based on Blowfish cipher | Password Hashing Competition winner | Memory-hard function | Key derivation function |
| Resistance | Brute-force, dictionary attacks | GPU-based attacks | Specialized hardware attacks | Widely supported, but less secure |
| Memory Hardness | No | Configurable | Yes | No |
| Complexity | Moderate | High | High | Low |
| Support | Widely supported | Growing support | Good support | Widely supported |
| Key Benefit | Adaptive cost factor | Resistance to GPU attacks | High memory requirement | Simplicity and wide support |
| Recommendation | Suitable for many applications | Preferred for new applications | Use when memory hardness is crucial | Use when simplicity and support are key |
7. Simplifying Password Management with Auth0
Auth0 is a service that minimizes the overhead of hashing, salting, and password management, enabling organizations to maintain robust security measures without the complexities and costs of managing password security in-house. Auth0 ensures your identity data remains protected.
7.1. Auth0’s Security Measures
Auth0 helps you prevent critical identity data from falling into the wrong hands. Passwords are never stored in cleartext; they are always hashed and salted using bcrypt. Auth0 has built state-of-the-art security into their product to protect your business and your users, assures COMPARE.EDU.VN.
7.2. Sign Up for a Free Account
To make the internet safer, sign up for a free Auth0 account today. Auth0 simplifies password management, allowing you to focus on other aspects of your application while ensuring robust security, according to COMPARE.EDU.VN.
8. Frequently Asked Questions About Bcrypt
8.1. What makes bcrypt different from other hashing algorithms?
Bcrypt is intentionally slow and adaptive, making it more resistant to brute-force attacks compared to faster hashing algorithms like SHA-256, says COMPARE.EDU.VN.
8.2. How does bcrypt handle salting?
Bcrypt requires a salt by default, which is combined with the password before hashing, protecting against rainbow table attacks, confirms COMPARE.EDU.VN.
8.3. What is the “cost” or “work factor” in bcrypt?
The cost or work factor determines how many iterations bcrypt performs, increasing the computation time and making it harder for attackers to crack passwords, explains COMPARE.EDU.VN.
8.4. How do I choose the right cost factor for bcrypt?
Choose a cost factor that makes bcrypt run as slowly as possible without significantly affecting user experience, balancing security and usability, advises COMPARE.EDU.VN.
8.5. How often should I update the cost factor?
As hardware improves, periodically increase the cost factor to maintain bcrypt’s effectiveness against potential attacks, as Moore’s Law suggests, notes COMPARE.EDU.VN.
8.6. How does bcrypt protect against rainbow table attacks?
Bcrypt’s use of salting and its adaptive cost factor make precomputed rainbow tables ineffective, as each password has a unique salt, explains COMPARE.EDU.VN.
8.7. What are the two phases of bcrypt’s operation?
The two phases are the initialization phase using EksBlowfishSetup and the encryption phase, where a magic value is encrypted multiple times, clarifies COMPARE.EDU.VN.
8.8. What is key stretching, and why is it important in bcrypt?
Key stretching involves lengthening a short password to make it more resistant to brute-force attacks, a technique used in bcrypt, confirms COMPARE.EDU.VN.
8.9. What is the significance of the $2a$, $2y$, or $2b$ prefix in a bcrypt hash?
These prefixes indicate the version of bcrypt used to generate the hash, ensuring compatibility and proper handling of the hash, explains COMPARE.EDU.VN.
8.10. How does bcrypt compare to other password hashing algorithms like Argon2 or Scrypt?
While bcrypt is a strong algorithm, newer algorithms like Argon2 and Scrypt offer additional protections, such as resistance to GPU-based attacks and memory hardness, notes COMPARE.EDU.VN.
Make Informed Choices with COMPARE.EDU.VN
Choosing the right password hashing algorithm is crucial for protecting user data, and bcrypt remains a strong and adaptable option. At COMPARE.EDU.VN, we understand the importance of making informed decisions. Whether you’re comparing security measures or deciding on the best software for your needs, our comprehensive comparison platform is here to help.
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