TFT

Bcrypt Hash Generator & Verifier

Hash passwords securely with bcrypt, including a cost factor for adjustable security. Verify existing bcrypt hashes against plaintext passwords to test login credentials.

Hash Algorithm Analysis

Password Strength Analysis

Password Hash Security

Not all hash algorithms are suitable for password storage. Fast hashes like MD5 and SHA-256 are vulnerable to brute-force attacks. Use specialized password hashing algorithms like bcrypt, Argon2, or scrypt that are intentionally slow and memory-hard.

How Bcrypt Password Hashing and Verification Works

Bcrypt is a password hashing function designed by Niels Provos and David Mazières in 1999. It's based on the Blowfish cipher and includes a built-in salt and configurable cost factor to slow down brute-force attacks.

This tool generates bcrypt hashes with adjustable cost factors and verifies existing hashes against plaintext passwords. The verification process extracts the salt and cost from the stored hash, applies them to the input password, and compares results.

Here's the process:

  1. Random salt is generated (128 bits)
  2. Password and salt are processed through EksBlowfishSetup
  3. Multiple rounds (2^cost) of key expansion occur
  4. Final hash includes cost, salt, and hashed password

Security status: Bcrypt remains a recommended password hashing algorithm by OWASP. While Argon2 is newer, bcrypt is battle-tested and widely supported.

When You'd Actually Use This

Secure password storage

Hash user passwords before database storage. Bcrypt's adaptive cost factor ensures hashes remain slow to crack even as hardware improves over time.

Login system testing

Generate test bcrypt hashes to verify your authentication code. Ensure your login system correctly verifies passwords against stored bcrypt hashes.

Password migration

Upgrade from weaker hashes (MD5, SHA-1) to bcrypt. Generate bcrypt hashes for existing passwords during user login, gradually migrating your user base.

Security compliance

Meet OWASP, PCI-DSS, or other security standards requiring strong password hashing. Bcrypt satisfies requirements for adaptive, salted password hashing.

Hash format verification

Verify bcrypt hashes from different systems. Check if hashes are valid bcrypt format and test verification logic across different bcrypt implementations.

Educational demonstrations

Show how cost factor affects hashing time. Demonstrate why bcrypt is more secure than simple hashes by comparing computation times and cracking resistance.

What to Know Before Using Bcrypt

Cost factor controls security. The cost (also called work factor) determines iterations as 2^cost. Cost 10 = 1024 rounds, cost 12 = 4096 rounds. Higher cost = more secure but slower.

Bcrypt includes salt automatically. Each hash contains its own random salt. You don't need to manage salt separately—just store the full hash string.

Hash format is standardized. Bcrypt hashes start with $2a$, $2b$, or $2y$ followed by cost and salt. Example: $2a$10$... means version 2a, cost 10.

72 character password limit. Bcrypt only processes the first 72 characters of a password. Longer passwords are truncated. This is rarely a practical limitation.

Pro tip: OWASP recommends cost 10 as minimum for 2024. Adjust based on your hardware—aim for 200-500ms per hash operation for interactive logins.

Common Questions

What cost factor should I use?

OWASP recommends cost 10 minimum (2024). For high-security applications, use cost 12-14. Test on your hardware—target 200-500ms for user logins, higher for background operations.

Why does bcrypt take so long?

That's the point. Bcrypt is intentionally slow to make brute-force attacks impractical. While MD5 takes microseconds, bcrypt takes hundreds of milliseconds—making cracking millions of passwords infeasible.

Can bcrypt hashes be cracked?

Weak passwords can still be cracked with enough time and resources. A strong password (12+ random characters) with cost 12+ would take centuries to crack with current technology.

What's the difference between $2a$, $2b$, and $2y$?

These are bcrypt version markers. $2a$ is standard, $2b$ fixes a bug in PHP's implementation, $2y$ is used by some languages. All are compatible for verification purposes.

How do I verify a bcrypt hash?

Extract the salt and cost from the stored hash, apply bcrypt to the candidate password with those parameters, and compare the results. Most libraries handle this automatically with a verify() function.

Is bcrypt better than Argon2?

Argon2 is newer and memory-hard (resistant to GPU attacks). Bcrypt is battle-tested and widely supported. Both are secure—Argon2 is preferred for new systems, bcrypt is fine for existing ones.

Is this tool safe for real passwords?

All processing happens locally in your browser—no data is transmitted. However, never test production passwords on any web tool. Use test credentials only.

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