What is Bcrypt Generator?
The Bcrypt Generator is a free online tool that creates secure password hashes using the bcrypt algorithm. Bcrypt is specifically designed for password hashing and includes built-in salting and adaptive cost factors to protect against brute-force and rainbow table attacks.
Unlike MD5 or SHA256, bcrypt is intentionally slow and can be configured to become slower over time as computers get faster. This makes it ideal for storing user passwords securely in databases.
Bcrypt was created by Niels Provos and David Mazieres in 1999, based on the Blowfish cipher. It is widely adopted by major frameworks and is recommended by security experts for password storage.
Why Use Bcrypt Generator?
- Built-in Salt — Automatically generates unique salts for each password to prevent rainbow table attacks
- Adaptive Security — Cost factor can be increased as hardware improves
- Brute-Force Resistant — Intentionally slow to make password cracking impractical
- Industry Standard — Used by WordPress, Django, Ruby on Rails, and many others
- Built-in Hash Verification — Same function verifies and updates password hashes
- OWASP Recommended — Approved by OWASP for secure password storage
- FIPS Compliant — Meets federal security standards for password protection
How Bcrypt Hashing Works
Bcrypt uses a sophisticated approach to password hashing that includes multiple security features:
- Salt Generation — Creates a random 128-bit salt for each password
- Key Setup — Initializes the Blowfish cipher with the salt and cost factor
- Expensive Key Schedule — Performs 2^cost iterations of Blowfish encryption
- Hash Output — Produces a 184-bit hash encoded as 60 ASCII characters
Understanding Bcrypt Cost Factor
What is Cost Factor?
The cost factor (also called "work factor") determines how many iterations the algorithm performs. Each increment doubles the time required, making brute-force attacks exponentially harder.
Cost Factor Guidelines
| Cost Factor | Time (approx) | Use Case |
|---|---|---|
| 4-5 | ~10-20ms | Testing only, not secure |
| 6-7 | ~50-100ms | Fast testing |
| 8 | ~200ms | Standard web applications |
| 10 | ~500ms | High security applications |
| 12 | ~1-2 seconds | Maximum security (slow logins acceptable) |
| 14+ | ~4+ seconds | Very high security only |
Bcrypt Hash Format
A bcrypt hash looks like this: $2a$10$N9qo8uLOickgx2ZMRZoMye1oG0t0t0t0t0t0t0t0t0t0t0t0t0
- $2a$ — Algorithm identifier (2a = current version)
- 10$ — Cost factor (10 rounds in this example)
- N9qo8uLOickgx2ZMRZoMye — 22-character salt (128 bits base64)
- IoG0t0t0t0t0t0t0t0t0t0t0t — 31-character hash (184 bits base64)
Bcrypt vs Other Password Hashing Methods
| Feature | MD5 | SHA256 | Bcrypt | Argon2 |
|---|---|---|---|---|
| Speed | Very Fast | Fast | Slow | Slow |
| Built-in Salt | No | No | Yes | Yes |
| Adaptive | No | No | Yes | Yes |
| Memory Hard | No | No | Partial | Yes |
| OWASP Approved | No | No | Yes | Yes |
| Recommended | Never | No | Yes | Yes (preferred) |
How to Use Bcrypt Generator
- Enter your password in the input field above
- Select the cost factor (10 is recommended for most applications)
- Click "Generate Bcrypt Hash"
- Copy the generated hash for storage in your database
- To verify passwords, compare the input hash with stored hash using bcrypt.compare()
Bcrypt Security Best Practices
Do's
- Use cost factor of 10 or higher for production
- Store the complete bcrypt hash including algorithm and cost
- Update hashes when users log in (periodically rehash with updated cost)
- Use HTTPS when transmitting password data
- Implement rate limiting on login attempts
Don'ts
- Never use cost factors below 10 for stored passwords
- Don't truncate or modify bcrypt hashes
- Don't use bcrypt for non-password purposes (it's optimized for passwords)
- Don't log password hashes or transmit them unnecessarily
- Don't use MD5 or SHA1 for passwords ever
Frequently Asked Questions
Why is bcrypt better than MD5 or SHA256 for passwords?
MD5 and SHA256 are designed to be fast, which makes them vulnerable to brute-force attacks. Bcrypt is intentionally slow and includes built-in salting, making it orders of magnitude harder to crack passwords.
What cost factor should I use?
For most web applications, cost factor 10 or 12 is recommended. The key is to make it slow enough to prevent attacks but fast enough not to degrade user experience. Modern servers can handle 10 comfortably.
Can I change the cost factor after hashing?
Yes. When a user logs in successfully, you can rehash their password with a higher cost factor and update the stored hash. This is called "hash upgrading."
How do I verify a password against a bcrypt hash?
Use bcrypt.compare(password, hash) which returns true if the password matches. Never decrypt the hash — bcrypt is a one-way function.
Is bcrypt secure enough for sensitive applications?
Yes. Bcrypt is approved by OWASP and widely considered one of the most secure password hashing methods available. For maximum security, Argon2 is also an excellent choice.