How Password Hashing Protects User Credentials

Password hashing is a method to protect your passwords by using a cryptographic algorithm to turn it into a random string of characters. This scrambled version is called a hash, and it is stored in the database of the system instead of the actual password. During login, the system takes whatever you enter for a password and runs the same algorithm on it. The result is then compared to the already stored hash. If it is a match, you gain entry.
One significant thing to bear in mind: Hashing is a one-way function. This essentially means that once a password has been hashed, it cannot be transformed back into the original password. If somebody gets and steals the whole database, they would not straightforwardly know the passwords - that is, assuming the system uses a strong, modern hashing scheme.
The Problem with Weak Hashing Algorithms
In the past, various systems used simple algorithms like MD5 or SHA-1 to hash passwords. These functions run quickly and require low computational power—an attribute once seen as advantageous. Now, speed poses a risk: with modern hardware or cloud computing, attackers can perform billions of guesses per second on a hash.
Suppose a company stores password hashes with MD5. In that case, attackers could create a massive rainbow table—an precomputed list of hashes for common passwords—and recover the original passwords. In other words, a stolen database protected by MD5 allows even moderately skilled attackers to exploit it.
What Stronger Hashing Looks Like
Strong password hashing is based on deliberately slow and adaptive algorithms, including:
- Bcrypt
- Scrypt
- Argon2
These algorithms are designed programmatically to resist brute-force attacks. You can increase the computational cost as hardware improves, helping to future-proof password storage. One example is bcrypt, which uses a work factor that determines how long it takes to compute a hash. Raising this factor can make password cracking more time-consuming and resource-intensive. Another example is Argon2, which was the winner of the Password Hashing Competition held in 2015. It enhances resistance to GPU-based attacks and side-channel attacks, making it probably the best option available today.
Salting – Another Crucial Layer of Defense
Salt is a random string added to a password before hashing. Therefore, two identical passwords will not generate the same hash, making rainbow table attacks ineffective. Without salting, users with common passwords, like "123456" or "password," will have the same hash value. With the salt, even if two users select the same password, their hashes will appear completely different. Every properly implemented password hashing scheme uses a long, random, unique salt for each user.
Why This Matters for Privacy
When personal data is leaked during a breach, hashed passwords represent one of the most sensitive data types exposed. If weak or unsalted hashes are used, it can lead to attacks where the users' original passwords-and, by extension, their other accounts—are compromised. Since many people reuse passwords across different services, a cracked hash from one platform could jeopardize access to others.
Inadequate hashing also damages trust. Users expect organizations to protect their information. Not using a modern password hashing scheme is not just a technical mistake but also an infringement on that trust and a failure to follow accepted best practices.
Going Toward Safer Password Storage
Organizations should regularly review and update their password storage methods. Transitioning to stronger hashing algorithms can be gradual — passwords are rehashed when users log in, while systems adopt new standards by default for new accounts. Developers should avoid creating their own cryptographic solutions and should instead rely solely on vetted open-source libraries that follow these practices. Secure password storage is not something a system needs to feel special about — it is the foundation on which the system's security is built.
Summary
Insecure password hashing undermines user privacy and data security. The debate over relying on outdated algorithms like MD5 or SHA-1 in security-conscious environments is no longer relevant. Accordingly, slow and adaptive salted hashing algorithms like bcrypt and Argon2 should be adopted by organisations as their defensive tools against attackers. It protects an individual and also stands the test against contractual and public obligations.
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Security Tip: Use a unique password for each of your accounts. Consider using a password manager to keep track of them all securely. #Password #Security #StaySafe pic.twitter.com/f7wUaj1vwd
— Birak IT Services Southampton (@BirakIT) June 27, 2025