How does bcrypt work?

Bcrypt takes a password and a 'cost factor' (rounds), salts the password, and runs many iterations of the Blowfish-based key schedule. The result is a hash of the form: $2b$12$saltsalt...hashhash. The cost factor (default 10-12) controls slowness — higher = more secure but slower verification.

Why is bcrypt better than SHA-256?

SHA-256 is fast — attackers compute billions per second on GPUs. Bcrypt is slow (10ms+ per hash) — same attacker only computes hundreds per second. Combined with mandatory salt (preventing precomputed rainbow tables), bcrypt makes brute-force attacks impractical even with massive compute.

What cost factor should I use?

Current recommendation (2024): cost 12-14. Higher cost = slower hashing but more secure. Verify hashing takes 100-500ms on your server (acceptable user-facing latency). As compute power increases, gradually increase cost factor for new passwords.

Should I use bcrypt or argon2?

argon2 is newer (2015) and better in some ways (resistance to specialized hardware attacks, configurable memory cost). Bcrypt is older but very widely supported across languages/frameworks. For new code, prefer argon2 (specifically argon2id variant). Bcrypt remains acceptable for legacy systems.

Can I crack bcrypt hashes?

Effectively no, with strong passwords. Each guess takes the configured cost time (e.g., 200ms). For an 8-character password from 94-character pool: 94^8 = 6×10^15 guesses. At 200ms each, that's millions of years. Even fast GPU clusters struggle. Strong passwords + bcrypt = very secure.

What's the typical bcrypt hash format?

$2b$12$saltsaltsaltsalt22charshashhashhashhashhashhashhash. Format: $2b (algorithm version), $12 (cost factor), $22 chars (salt), then 31 chars (hash). Total ~60 characters. Different versions ($2a, $2b, $2y) have minor implementation differences but are mostly interchangeable.

Is the password sent anywhere?

No. Bcrypt hashing happens entirely in your browser. Your password is hashed locally — never transmitted. Useful for testing or generating example hashes for documentation. For production password storage, hash on your server with proper authentication framework.

Bcrypt Hash Generator

Generate bcrypt hash for passwords online with adjustable cost factor. Free bcrypt generator for secure password hashing and storage.

Hash & Crypto

Instant results

Generate Bcrypt Hash

Password to Hash

Salt Rounds: 10 (Cost factor: 2¹⁰ = 1,024 iterations)

Faster (4)Recommended (10-12)Slower (14)

Verify Password Against Hash

Bcrypt Hash

Password to Verify

Cost Factor Reference

RoundsIterationsUse Case

416Fast testing

8256Light security

101,024General purpose

124,096High security

1416,384Maximum security

About Bcrypt

Bcrypt is a password hashing algorithm based on the Blowfish cipher. It includes a built-in salt to protect against rainbow table attacks and a configurable cost factor that can be increased as hardware improves, keeping hashes resistant to brute-force attacks. This tool uses a full JavaScript implementation of bcrypt (bcryptjs) running entirely in your browser — your passwords are never sent to any server.

How to Use Bcrypt Hash Generator

Enter your password

Type the password to hash. The generator never displays or transmits the password — only the hash.

Choose cost factor

Set rounds (10-14 typical). Higher cost = slower but more secure. Default 12 is appropriate for most uses in 2024.

Generate hash

Click Generate; the bcrypt hash appears (format: $2b$12$saltsalt...hashhash). Copy the entire string for storage.

Use with verification

Store the hash; when verifying passwords, use bcrypt.compare(plaintext, hash) in your application code. Never store the original password.

When to Use Bcrypt Hash Generator

Password storage in applications

When building user authentication systems, hash passwords with bcrypt before storing in your database. Never store plaintext passwords. The generator shows what stored hashes look like; production systems should use bcrypt libraries directly in their language (bcryptjs, py-bcrypt, jBCrypt, etc.).

Securing API keys and secrets

API keys and shared secrets should be hashed (with salt) before storage, similar to passwords. Bcrypt provides strong protection against database breaches. If your database is stolen, attackers still can't easily recover the original keys.

Testing authentication code

When writing or reviewing authentication code, generate test bcrypt hashes for fixtures. Verify your code correctly handles the bcrypt format and verification flow without exposing real passwords in test data.

Migrating from MD5/SHA-1 password storage

Legacy systems often used MD5 or SHA-1 for passwords (insecure today). To migrate to bcrypt: when users log in, verify against old hash, then re-hash with bcrypt and update database. Helps secure old systems incrementally.

Bcrypt Hash Generator Examples

Standard bcrypt hash

Input

Password: mySecurePass123\nCost: 12

Output

$2b$12$N9qo8uLOickgx2ZMRZoMyeIjZAgcfl7p92ldGxad68LJZdL17lhWy

Bcrypt hash format: $2b (algorithm version), $12 (cost factor 12 means 4096 rounds), $22 chars (salt), 31 chars (actual hash). Total ~60 chars. Higher cost = slower verification but stronger security.

Same password, different hashes

Input

Password: mySecurePass123\nCost: 12 (run twice)

Output

Hash 1: $2b$12$abc...xyz\nHash 2: $2b$12$def...uvw

Different salt each time produces different hashes for same password — that's correct! The hash includes the salt; verification function extracts it and recomputes. This prevents rainbow table attacks.

Cost factor comparison

Input

Same password\nCost 8 vs Cost 14

Output

Cost 8: ~10ms\nCost 14: ~600ms

Each cost increment doubles the time. Cost 8 is too fast for modern hardware (attackers benefit too); Cost 14 is more secure but adds noticeable login latency. Cost 12 is current sweet spot.

Tips & Best Practices for Bcrypt Hash Generator

1.Never use raw SHA-256 or MD5 for passwords. Use bcrypt, argon2, or scrypt — purpose-built password hashing functions.
2.Cost factor 12 is reasonable for 2024. Plan to increase to 14 over the next few years as hardware improves. Adjust based on your acceptable login latency.
3.Bcrypt has a 72-byte input limit. Longer passwords are silently truncated (potentially causing security issues). Use argon2 for passwords longer than 72 bytes.
4.Always use a proper bcrypt library. Don't roll your own — implementation details matter for security. Bcryptjs (JS), py-bcrypt (Python), bcrypt (Node.js) are all good.
5.Hash on the server, not the client. Client-side hashing reveals the hash — equivalent to revealing the password. Always hash on trusted server-side code.
6.Consider argon2 for new applications. It's the modern choice (won the 2015 Password Hashing Competition) with tunable memory cost — making GPU/ASIC attacks harder.

Frequently Asked Questions

bcrypt is a password hashing function designed for storing passwords securely. Unlike fast hashes (MD5, SHA-256), bcrypt is intentionally slow — making brute-force attacks expensive. It also includes built-in salt (random data added to passwords to defend against rainbow tables). Industry standard for password storage since the early 2000s.

Bcrypt Hash Generator

Generate Bcrypt Hash

Verify Password Against Hash

Cost Factor Reference

About Bcrypt

How to Use Bcrypt Hash Generator

Enter your password

Choose cost factor

Generate hash

Use with verification

When to Use Bcrypt Hash Generator

Password storage in applications

Securing API keys and secrets

Testing authentication code

Migrating from MD5/SHA-1 password storage

Bcrypt Hash Generator Examples

Standard bcrypt hash

Same password, different hashes

Cost factor comparison

Tips & Best Practices for Bcrypt Hash Generator

Frequently Asked Questions

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