Do I need to store the salt with bcrypt?

security

password-management

hashing

salt-storage

byNikita Barsukov·Jan 27, 2025

Utilizing bcrypt, the salt is incorporated in the hash itself. So, no need to store the salt independently; bcrypt conveniently handles it for you. To validate passwords, you simply use the original hash. Bcrypt will extract the integrated salt and perform the comparison.

Here's a Java example:

// Cooking up some hashed password goodness with a sprinkle of salt.
String hashed = BCrypt.hashpw("yourPassword", BCrypt.gensalt());

// Later...
// Checks if the "gourmet dish" (password) you cooked up before matches the taste (hash).
// Yep, checking taste, not calories ;).
if (BCrypt.checkpw("yourPassword", hashed)) {
    // Passwords match. Culinary wizard confirmed 🧙🍳.
}

Just store the full hashed result; It's your salt and hash two-course meal.

How does bcrypt slip the salt into the hash?

bcrypt embeds the salt within the hash output. This intelligent design eliminates the need for separate salt storage and streamlines the authentication process:

Unique Salt Per Hash: Like snowflakes, no two salts in bcrypt are identical. This means even identical passwords have different hashes.
No Extraction Needed: The salt is well masked within the hash, and compared automatically by the verification function.
Easy Validation: While checking passwords, bcrypt takes care of the salt extraction and usage for you.

This integral solution by bcrypt decreases storage requirements, eliminates need for separate salt management and thus reduces potential vulnerabilities.

Comparing bcrypt with traditional salt and hash systems

With bcrypt-based systems:

The salting process is automated and inbuilt.
Separate salt storage is unwarranted compared to legacy systems.
Concerns about salt leaks are minimal, since they're incorporated in the hash and the hash alone is useless without correct password.

In contrast, traditional systems like Unix password schemes:

Required separate salt storage as part of the password, often the first two characters.
This entails additional code for handling and storage.
It could be error-prone if the link between password and salt isn't meticulously maintained.

bcrypt overrides these historical complexity by packaging each hashed password with a non-separable salt.

Key considerations for secure implementation

Handling Hashes Mindfully

While bcrypt eradicates the need for storing salt, handling the hash still requires care:

Make sure to securely store the bcrypt hash in your database.
Protect the integrity of the hashing process by adding additional security layers, like SSL/TLS during data transmission.

Increasing Security Bandwidth with Salts

Salts play a critical role in enhancing hashed password security against potential attacks:

Rainbow table attacks: These attacks use pre-computed tables for reversing hash functions, which a unique salt for every password makes ineffective.
Brute-force attacks: Salts increase the time and cost of these attacks by requiring a separate operation for each uniquely salted hash.

bcrypt's Capability to Scale

bcrypt was designed to withstand the increasing computing power. The adjustable difficulty (work factor) in bcrypt ensures it remains relevant and robust for future security requirements.

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