Bcrypt Generator Hash generators

What is Bcrypt?

Bcrypt is a password hashing function designed by Niels Provos and David Mazières, based on the Blowfish cipher. It incorporates a salt to protect against rainbow table attacks and is adaptive, allowing the iteration count to be increased to make it slower and more resistant to brute-force attacks.

How Bcrypt Works

Bcrypt uses the Eksblowfish algorithm, an enhanced version of Blowfish that requires an expensive key setup phase. The algorithm:

• Key Setup: Derives an encryption key from the password using the costly Eksblowfish key schedule
• Salt Generation: Creates a 128-bit random salt for each password
• Cost Factor: Performs 2^cost iterations, making brute-force attacks computationally expensive
• Output Format: Produces a 60-character string containing version, cost, salt, and hash

Security Considerations

Hash Format

• $2y$ - Algorithm identifier (2y = current version)
• 10 - Cost factor (2^10 = 1,024 rounds)
• N9qo8uLO... - Salt (22 characters)
• IjZAgcfl... - Hash (31 characters)

Cost Factor Guidelines

PHP

// Generate hash
$password = 'MySecurePassword123!';
$hash = password_hash($password, PASSWORD_BCRYPT, [
    'cost' => 12
]);

// Verify password
if (password_verify($password, $hash)) {
    echo 'Password is valid!';
} else {
    echo 'Invalid password.';
}

// Get hash info
$info = password_get_info($hash);
print_r($info);

Node.js

const bcrypt = require('bcrypt');

// Generate hash
const password = 'MySecurePassword123!';
const saltRounds = 12;

// Async
bcrypt.hash(password, saltRounds, (err, hash) => {
    console.log(hash);
});

// Sync
const hash = bcrypt.hashSync(password, saltRounds);

// Verify
bcrypt.compare(password, hash, (err, result) => {
    console.log(result); // true
});

Python

import bcrypt

# Generate hash
password = b'MySecurePassword123!'
salt = bcrypt.gensalt(rounds=12)
hashed = bcrypt.hashpw(password, salt)

# Verify password
if bcrypt.checkpw(password, hashed):
    print("Password matches")
else:
    print("Password does not match")

Java

import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;

BCryptPasswordEncoder encoder = new BCryptPasswordEncoder(12);

// Generate hash
String password = "MySecurePassword123!";
String hashedPassword = encoder.encode(password);

// Verify password
boolean matches = encoder.matches(password, hashedPassword);

Security Best Practices

Migration Strategy

If you're migrating from a weaker hash function:

1. When user logs in, verify with old hash
2. If valid, hash with bcrypt and update database
3. Mark account as migrated
4. After grace period, require password reset for non-migrated accounts

Performance Considerations

• Bcrypt is CPU-intensive by design
• Consider async hashing to avoid blocking
• Cache cost factor benchmarks per server
• Monitor hash generation time in production
• Balance security with user experience

Common Use Cases

Implementation Examples

Frequently Asked Questions

Technical Specifications