Bcrypt Generator

How to Use

1. Choose the mode: click Hash to generate a bcrypt hash from text, or Verify to compare plaintext against an existing hash.
2. In Hash mode, enter the text you want to hash in the input field.
3. Select the cost rounds (4–12). Higher rounds = more secure but slower. The default of 10 is recommended for most use cases and takes approximately 100ms.
4. Click the Hash button. The estimated time display shows how long the operation is expected to take.
5. Copy the resulting hash with the Copy Hash button.
6. In Verify mode, enter the plaintext in the top field and paste a bcrypt hash in the bottom field.
7. Click Verify to check if the plaintext matches the hash. The tool validates the hash format before comparing.
8. Click Load Example to try the tool with sample data, or Clear to reset all fields.

Bcrypt vs Other Hash Algorithms

When it comes to password storage, not all hash algorithms are created equal. MD5 and SHA-1 are general-purpose cryptographic hash functions designed to be fast — they can compute millions of hashes per second on a modern GPU. This speed is their downfall for password security: if an attacker obtains your password database, they can try billions of password guesses per second against MD5 or SHA-1 hashes. SHA-256 and SHA-512 are similarly fast, making them equally unsuitable for password storage without additional iterations (which is what PBKDF2 does).

Bcrypt is fundamentally different. Its adaptive cost factormeans you can increase the difficulty over time as hardware gets faster. A cost factor of 10 (the default) means 2^10 = 1,024 iterations of the key schedule, taking roughly 100ms. At cost 12, that becomes about 400ms. At cost 14, over 1.5 seconds. This makes brute-forcing a bcrypt hash orders of magnitude more expensive than an SHA-256 hash. A GPU that can try 50 billion MD5 hashes per second might only manage a few thousand bcrypt attempts — a difference of millions of times.

Bcrypt also has a maximum input length of 72 bytes. For most passwords this is not an issue, but if you are hashing long passphrases, you should pre-hash them with a fast algorithm like SHA-256 and then bcrypt the result. Other password-specific algorithms like scrypt and Argon2 offer additional protections (memory hardness), but bcrypt remains the most widely supported and battle-tested option for password storage.

Security Best Practices

• Use cost factor 10–12 for new applications. This provides a good balance of security and performance. The NIST recommends periodically increasing the cost factor as hardware improves.
• Never store plaintext passwords. Always hash them with bcrypt (or Argon2/scrypt) before saving to a database. If your database is compromised, hashed passwords are still difficult to crack.
• Let bcrypt generate the salt for you. Bcrypt embeds the salt directly in the hash output, so you only need to store the single hash string. Never reuse salts across passwords.
• Do not use MD5, SHA-1, or plain SHA-256 for passwords. These are general-purpose hashes, not password hashes. They are too fast and lack salting, making them vulnerable to rainbow table and brute-force attacks.
• Re-hash when upgrading cost factor. When a user logs in and you verify their password, check the cost factor in their existing hash. If it is lower than your current target, re-hash the password with the new cost and update the stored hash.
• Use unique passwords for each account. Even with bcrypt, if two accounts use the same password, the hashes will differ due to unique salts — but using unique passwords protects you if one account is compromised through other means.
• This tool runs 100% client-side. Your text is never sent to a server or stored anywhere. All hashing and verification happens in your browser using JavaScript, making it safe to use even with sensitive passwords.