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    Bcrypt Hash Generator

    Generate and verify bcrypt password hashes in your browser.

    🔒 All hashing is done in your browser using PBKDF2 (WebCrypto API). Your data never leaves your device.
    Cost factor (rounds): 10~20ms
    Higher = slower = more secure. 10-12 recommended for most use cases.
    ⚠️ This uses PBKDF2-SHA256 (WebCrypto) as a browser-compatible alternative to bcrypt. For production password hashing, use bcrypt or Argon2 on the server side.
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    What Is Bcrypt?

    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 and SHA, bcrypt is intentionally slow — this is a feature, not a bug. By making each hash computation expensive, bcrypt makes brute-force attacks impractically slow. The "cost factor" parameter lets you increase the computation time as hardware gets faster, future-proofing your password storage.

    The Cost Factor

    Bcrypt's cost factor (also called work factor or rounds) determines how computationally expensive the hash is. The actual iterations are 2^cost — so cost 10 means 1,024 iterations, cost 12 means 4,096 iterations. As computing power increases, you can increase the cost factor. Most security experts recommend cost 10-12 for web applications in 2025. Each increment doubles the time required, so cost 12 takes 4x longer than cost 10.

    Bcrypt vs Argon2 vs PBKDF2

    Bcrypt remains widely used and trusted. Argon2 (winner of the Password Hashing Competition in 2015) is the newest standard, with variants for different threat models: Argon2d (GPU-resistant), Argon2i (side-channel resistant), and Argon2id (hybrid). PBKDF2 is the oldest, used in WPA2 WiFi and many enterprise systems. Scrypt adds memory-hardness to prevent GPU attacks. For new projects, Argon2id is recommended; bcrypt remains an excellent choice.

    Why MD5 and SHA Are Not Suitable

    MD5 and SHA algorithms are designed to be fast — they can compute billions of hashes per second on modern GPUs. This speed makes them terrible for password hashing because attackers can try billions of password guesses per second. MD5 also has known collision vulnerabilities. While SHA-256 is cryptographically secure for checksums and digital signatures, its speed makes it unsuitable for password storage without additional measures like PBKDF2's key stretching.

    Rainbow Tables and Salting

    Rainbow tables are precomputed lookup tables that map hashes back to passwords. Without salting, identical passwords produce identical hashes — so one rainbow table cracks all users with that password. Bcrypt automatically generates a unique random salt for each password and embeds it in the output hash. This means even identical passwords produce different hashes, making rainbow tables completely useless against bcrypt-hashed passwords.

    Frequently Asked Questions

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