Bcrypt Generator
What Is Bcrypt Hashing?
Bcrypt is a password hashing function designed by Niels Provos and David Mazières in 1999, based on the Blowfish cipher. Unlike fast hashing algorithms like MD5 or SHA-256, bcrypt is intentionally slow and computationally expensive, making it the gold standard for securely storing passwords. The key feature that sets bcrypt apart is its configurable cost factor (also called work factor or rounds): increasing the cost factor exponentially increases the time required to compute each hash, which means bcrypt can be tuned to remain secure even as hardware gets faster. Each bcrypt hash also includes a randomly generated salt, which is embedded directly in the output string — this prevents rainbow table attacks and ensures that identical passwords produce different hashes. The output format follows the Modular Crypt Format: $2b$cost$salt+hash. Bcrypt is recommended by OWASP, NIST, and virtually every security authority for password storage, and it is the default password hasher in frameworks like Laravel, Ruby on Rails, Django, and Spring Security.
How to Use the Bcrypt Generator
- Enter your password or string in the input field — this is the plaintext value you want to hash.
- Select the cost factor (rounds) — the default of 10 is suitable for most applications. Higher values (12–14) provide more security but take longer to compute. Each increment doubles the computation time.
- Click "Generate" to produce the bcrypt hash. The output will be a 60-character string starting with
$2b$or$2a$. - Copy the hash and store it in your database. To verify a password later, use bcrypt's verify function — never compare hashes directly since the random salt makes each hash unique.
Common Use Cases
- User password storage: Hash user passwords with bcrypt before storing them in your database to protect against data breaches.
- Password migration: Generate bcrypt hashes when migrating from weaker hashing schemes like MD5 or SHA-1 to a modern algorithm.
- API key hashing: Store bcrypt hashes of API keys so that even if your database is compromised, the original keys cannot be recovered.
- Testing and development: Generate bcrypt hashes for seed data, test users, or database fixtures during application development.
- Security auditing: Verify that your application correctly implements bcrypt by comparing generated hashes against known test vectors.
- Password verification: Check whether a plaintext password matches a stored bcrypt hash to debug authentication issues.
Frequently Asked Questions
What cost factor should I use for bcrypt?
For most web applications in 2024–2026, a cost factor of 10 to 12 provides a good balance between security and performance. At cost 10, hashing takes roughly 100 milliseconds on modern hardware; at cost 12, it takes about 300–400 milliseconds. Choose a cost factor that keeps login response times acceptable for your users while being slow enough to deter brute-force attacks. Increase it over time as hardware improves.
Why does bcrypt produce a different hash each time?
Bcrypt automatically generates a random 128-bit salt for every hash operation, and this salt is included in the output string. Because the salt is different each time, the same password will always produce a different hash. This is a critical security feature — it prevents attackers from using precomputed rainbow tables and ensures that two users with the same password will have completely different stored hashes in your database.
Is bcrypt better than SHA-256 for passwords?
Yes, bcrypt is significantly better than SHA-256 for password hashing. SHA-256 is a general-purpose hash function designed to be fast, which means attackers can compute billions of SHA-256 hashes per second using GPUs. Bcrypt is specifically designed to be slow and resistant to hardware acceleration, making brute-force attacks orders of magnitude more expensive. Always use bcrypt, scrypt, or Argon2 for password storage — never use SHA-256 or MD5.
