What is password hashing?

Password hashing: A complete guide

As cyberattacks and data breaches become more frequent, password security is more important than ever. One of the most effective ways to protect passwords is through password hashing. Storing passwords securely is crucial to protect against security risks associated with plaintext passwords in databases. But what exactly is password hashing, and how does it keep your data safe?

In this article, we explain how password hashing works, why it matters, and how techniques like salting and peppering make it stronger.

What is password hashing?

Password hashing is a cryptographic method that turns a password into a unique string of characters. This string is called a hash and is what websites store instead of your actual password. The hash function plays a crucial role in this process by converting the password into the hash, ensuring unique identification and resistance to manipulative attacks. The idea is that even if a hacker gains access to the database, they will only see the hashed version and not the real password.

Hashing is a one-way process. It cannot be reversed to reveal the original password. That makes it a fundamental part of modern cybersecurity.

Introduction to password hashing

Password hashing is a crucial aspect of password management, essential for secure password storage and verification. When a user creates a password, it is transformed from a readable plaintext password into a fixed-length string of characters using a hashing algorithm. This transformation results in a hashed password, which is stored securely in a database.

The primary purpose of password hashing is to ensure that even if a hacker gains access to the database, they cannot easily retrieve the original passwords. Hashing is a one-way function, meaning it takes readable text and transforms it into a completely different string of characters with a set length. This process is irreversible, making it impossible to revert the hashed password back to its original form.

Hashing algorithms are designed to scramble data, making it unreadable and secure. Companies use these algorithms to store passwords securely in their databases. When a user attempts to log in, the entered password is hashed and compared to the stored hash. If the hashes match, access is granted.

While password hashing significantly enhances security, it is not foolproof. Certain types of attacks, such as brute force attacks and dictionary attacks, can still pose a threat. Therefore, using strong passwords and password managers is essential to protect users’ sensitive information.

Understanding hash functions

Hash functions are a type of algorithm used to transform input data of any size into a fixed-size string of characters, known as a hash value. These functions are designed to be one-way, meaning it’s easy to generate a hash value from input data, but it’s computationally infeasible to recreate the original data from the hash value.

Hash functions play a vital role in various applications, including password storage, data integrity, and digital signatures. There are different types of hash functions, with cryptographic hash functions being the most secure. Cryptographic hash functions are designed to be collision-resistant, preimage-resistant, and second-preimage-resistant, ensuring that it is extremely difficult to find two different inputs that produce the same hash value.

Examples of cryptographic hash functions include SHA-256, SHA-512, and BLAKE2. These functions are used to verify the integrity of data by comparing the expected hash value with the actual hash value of the data. They are also used to authenticate users by storing a hashed version of their password and comparing it with the hash of the input password.

Hash functions are an essential component of modern cryptography, providing security and integrity in various applications. Understanding hash functions is crucial for developing secure password storage and verification systems.

How does password hashing work?

When you create or update a password on a website, the password is processed through a hashing algorithm. This algorithm generates a string of random-looking characters, which is stored in the website’s database.

Storing plaintext passwords in databases poses significant security risks, as attackers can easily exploit reused passwords and access sensitive user information during breaches. Using password hashing transforms plaintext passwords into hashes, reducing the likelihood of exposing sensitive data.

Later, when you log in, the password you enter is run through the same algorithm. If the resulting hash matches the one stored in the database, the system confirms that you entered the correct password and grants access.

This process is nearly instant and invisible to the user.

Popular hashing algorithms

There are many types of hashing algorithms. Some are outdated, while others are still secure and widely used.

• MD5 and SHA-1 were once common but are no longer considered secure. They are vulnerable to brute-force attacks.

• SHA-256, part of the SHA-2 family, is still strong and used in many systems today.

• Bcrypt, scrypt, and Argon2 are modern algorithms designed for password hashing. They are adaptive and can be configured to use more computing power, making them harder to crack.

Cryptographic hash functions (CHFs) are specialized algorithms designed for cryptographic applications, emphasizing their importance in information security. They are used in various applications, including digital signatures and message authentication codes, and provide protections against deliberate attacks, unlike non-cryptographic hash functions.

These algorithms ensure that the same input always gives the same output. However, they do not reveal anything about the original password.

Bcrypt algorithm

The bcrypt algorithm is a password hashing algorithm that uses a combination of hashing and salting to securely store passwords. Bcrypt is designed to be slow and computationally expensive, making it more resistant to brute-force attacks. This means that even if an attacker tries to guess the password by trying every possible combination, the process will be time-consuming and resource-intensive.

Bcrypt uses a salt value to make the hashing process more complex and secure. The salt is a random string added to the password before hashing, ensuring that even if two users have the same password, their hashed passwords will be different. This added complexity makes it much harder for attackers to use precomputed tables, such as rainbow tables, to crack the passwords.

The bcrypt algorithm is widely used in password storage and verification systems due to its high security and resistance to attacks. It is considered a secure password hashing algorithm and is recommended for use in modern applications. One of the key features of bcrypt is its adaptability to future changes in computing power and attack methods. Bcrypt uses a work factor to control the computational overhead of the hashing process, allowing it to remain secure as technology advances.

Understanding the bcrypt algorithm is essential for developing secure password storage and verification systems. Its combination of hashing, salting, and computational expense makes it a robust choice for protecting user passwords in various applications, including web servers, databases, and operating systems.

Why hashing alone is not enough

Even though password hashing adds protection, it is not foolproof. Hackers have methods to break hashed passwords.

Different hash functions have their own limitations and applications in security, making it crucial to choose the right one for specific needs. Cryptographic hash functions are designed for security purposes, while non-cryptographic hash functions are used for tasks like data retrieval and checksums.

Dictionary attacks

Hackers use software to run a list of common passwords through popular hashing algorithms. If one of the resulting hashes matches the data they have, they can figure out the original password.

Attackers often use precomputed hashes to crack passwords by matching them with the hash output.

Rainbow tables

Rainbow tables contain precomputed hashes of commonly used passwords. Hackers can search these tables for a match with a stolen hash. If they find one, they can identify the original password.

To defend against these methods, websites use extra protection such as salting and peppering.

What is salting?

Salting adds a random string of characters to a password before hashing it. This means that two users with the same password will have completely different hashes.

Adding salt is a critical security measure that enhances the uniqueness of each hashed password, making it significantly harder for attackers to reverse-engineer passwords.

Salts are unique for each user and stored alongside the hashed password in the database.

Benefits of salting

• It ensures each password has a unique hash, even if users choose the same password.

• A random salt enhances the uniqueness of each hashed password by generating a unique value that is added to the plaintext password before hashing.

• It prevents the use of rainbow tables.

• It makes dictionary attacks more difficult.

What is peppering?

Peppering is another layer of protection. Unlike salting, the pepper is a fixed secret string applied to all passwords. It is stored separately from the main database.

This adds an extra challenge for attackers. Even if they steal the hashes and salts, they still need access to the pepper to reverse the hash.

How peppering works

The pepper is static and used for all users on a website. It is not stored with the password data. It adds secrecy and complexity to the hashing process.

However, it is important to note that while encrypting passwords provides a layer of protection against unauthorized access, the encryption keys themselves pose a risk. If hackers gain access to these keys, they can potentially decrypt the passwords, making it crucial to safeguard the keys as they could facilitate broader breaches within the network.

When used together, salting and peppering make it extremely difficult for hackers to crack passwords.

How hackers crack hashed passwords

Despite these protections, attackers still attempt to break password security using:

• Brute-force attacks, where they try every possible password combination.

• Credential stuffing, where they reuse stolen password data from previous leaks.

• Hash collisions, rare situations where two different passwords produce the same hash.

Using modern algorithms like bcrypt or Argon2 along with salting and peppering greatly reduces the risk of these attacks succeeding.

How to protect your passwords

You can improve your password security by following these best practices:

Using complex passwords is crucial to enhance security against brute-force attacks and prevent unauthorized access. Consider utilizing password managers to generate unique and complex passwords as a proactive measure to avoid common vulnerabilities associated with password reuse across multiple sites.

Use strong passwords

Create passwords that are long, unique, and complex. Include a mix of uppercase and lowercase letters, numbers, and symbols.

Using the same password across multiple accounts can significantly increase the risk of unauthorized access, as attackers often exploit this vulnerability through techniques like password spraying.

Need guidance on building a strong password? Read our guide on how to choose a strong password to boost your online safety.

Use a password manager

A password manager can store and encrypt your passwords. It also helps you generate secure, unique passwords for each account.

When managing passwords, it is crucial to take security considerations into account to protect against potential vulnerabilities and enhance user authentication. Explore how password managers can strengthen your digital security.

Enable two-factor authentication

Adding a second step to your login process increases security. Even if your password is compromised, the attacker would still need a second form of authentication. Learn how two-factor authentication can better protect your accounts and data.

Stay informed about cybersecurity

Regular cybersecurity awareness training can help you stay ahead of threats and develop good habits that protect your data.

Additionally, it is crucial to choose a reliable service provider, as their handling of data plays a significant role in ensuring password security.

Conclusion: Is password hashing secure?

Password hashing is one of the best tools we have to protect sensitive data. When used with salting and peppering, it becomes even stronger. These methods make it extremely difficult for attackers to crack passwords, even weak ones.

Unlike encryption, which is a reversible method used to protect data that needs to be accessed later, password hashing is designed to be a one-way function, making it more secure for storing passwords.

As a user, you play an important role in your own security. By choosing strong passwords, using password managers, and enabling two-factor authentication, you create multiple layers of defense.

Hashing is not just a technical feature. It is a vital part of keeping your digital identity safe.