Introduction to Bcrypt Password Hashing
Bcrypt is a password-hashing function designed specifically for secure password storage. It's based on the Blowfish cipher and is intentionally slow to resist brute-force attacks. Understanding bcrypt and implementing it correctly is crucial for application security. This guide covers best practices for using bcrypt hash generators securely.
What is Bcrypt?
Bcrypt is a password-hashing algorithm that:
- Uses a work factor (cost parameter) to control hashing speed
- Automatically handles salt generation and inclusion
- Is designed to be slow to resist brute-force attacks
- Produces hashes that include algorithm, cost, and salt information
Why Use Bcrypt for Passwords?
Bcrypt is ideal for password hashing because:
- Designed for Passwords: Specifically created for password storage
- Adaptive Cost: Work factor can be increased as hardware improves
- Built-in Salt: Automatically generates and includes salt
- Slow by Design: Resists brute-force and rainbow table attacks
- Widely Supported: Available in most programming languages
Bcrypt Work Factor
What is Work Factor?
The work factor (cost parameter) controls how many iterations bcrypt performs. Higher work factors mean slower hashing but better security. Common values range from 10-12 for most applications.
Choosing Work Factor
Balance security and performance:
- Work Factor 10: Good default for most applications (~100ms)
- Work Factor 12: Higher security, slower (~400ms)
- Work Factor 14+: Very high security, very slow (seconds)
Using Our Bcrypt Generator
Our free bcrypt generator:
- Enter the password to hash
- Select work factor (cost parameter)
- Click generate to create bcrypt hash
- Copy the generated hash for use
The tool processes passwords entirely in your browser for privacy and security.
Bcrypt Security Best Practices
1. Never Store Plain Text Passwords
Always hash passwords before storing. Never store passwords in plain text, even temporarily.
2. Use Appropriate Work Factor
Use work factor 10-12 for most applications. Increase for high-security applications, but balance with performance.
3. Always Use Bcrypt for Passwords
Use bcrypt specifically for passwords. Don't use fast hashes like MD5 or SHA-256 for password storage.
4. Verify Passwords Correctly
Use bcrypt's built-in verification function. Don't manually compare hashes or extract salts.
5. Handle Errors Securely
Don't reveal whether a username exists through error messages. Use generic error messages for both invalid username and password.
Bcrypt Hash Structure
Bcrypt hashes contain:
- Algorithm identifier ($2a$, $2b$, or $2y$)
- Work factor (cost parameter)
- Salt (22 characters)
- Hash (31 characters)
Example: $2a$10$N9qo8uLOickgx2ZMRZoMyeIjZAgcfl7p92ldGxad68LJZdL17lhWy
Password Verification
How Verification Works
Bcrypt verification:
- Extracts salt and work factor from stored hash
- Hashes the provided password with the same salt and work factor
- Compares the resulting hash with the stored hash
Using Verification Functions
Always use bcrypt's built-in verification function. Never manually compare hashes or extract salts.
Common Bcrypt Mistakes
- Too Low Work Factor: Using work factor below 10
- Manual Salt Handling: Trying to manually generate or handle salts
- Hash Comparison: Manually comparing hashes instead of using verification
- Reusing Hashes: Using the same hash for multiple passwords
- Storing Plain Text: Storing passwords in plain text anywhere
Bcrypt vs Other Password Hashes
Bcrypt vs Argon2
Argon2 is newer and considered more secure, but bcrypt is more widely supported and still very secure.
Bcrypt vs PBKDF2
PBKDF2 is NIST-approved and widely available, but bcrypt is often easier to use and configure.
Bcrypt vs scrypt
scrypt is memory-hard and good for high-security needs, but bcrypt is simpler and more widely supported.
Implementation Guidelines
1. Use Established Libraries
Use well-tested bcrypt libraries for your programming language. Don't implement bcrypt yourself.
2. Handle Errors Properly
Handle bcrypt errors securely. Don't expose implementation details through error messages.
3. Update Work Factors
Consider increasing work factors over time as hardware improves. Re-hash passwords on next login when increasing work factor.
4. Test Thoroughly
Test password hashing and verification thoroughly. Ensure edge cases are handled correctly.
Security Considerations
Password Requirements
Implement strong password requirements (length, complexity) in addition to secure hashing.
Rate Limiting
Implement rate limiting on login attempts to prevent brute-force attacks.
Account Lockout
Consider account lockout after multiple failed login attempts, but be careful not to enable denial-of-service attacks.
Conclusion
Bcrypt is an excellent choice for password hashing. Following security best practices ensures your password storage is secure and resistant to attacks. Our bcrypt generator helps you create secure password hashes quickly and easily.
Remember: Never store plain text passwords, use appropriate work factors, always use bcrypt for passwords, verify passwords correctly, and handle errors securely. Good password hashing is fundamental to application security.
Use our bcrypt generator to create secure password hashes. Proper password hashing protects user accounts and is essential for secure applications.