About the Bcrypt Hash Generator & Verifier
Bcrypt is a widely used, purpose-built password hashing algorithm designed to be deliberately slow and resistant to brute-force attacks, making it a standard choice for securely storing user passwords in applications and databases. This tool generates a bcrypt hash from any password, or verifies whether a plain-text password matches an existing bcrypt hash — both entirely in your browser.
This tool is useful for developers testing authentication code without needing to run a backend script, database administrators manually inserting or verifying a user record's password hash, and students learning how password hashing works in practice.
To use it, switch between "Hash" mode (enter a plain password and a cost factor/rounds value to generate a bcrypt hash) and "Verify" mode (enter a plain password and an existing bcrypt hash to check whether they match). Hashing generates a properly formatted bcrypt string (starting with $2a$, $2b$, or $2y$) including the embedded salt and cost factor, ready to store or compare.
For example, hashing the password "correcthorsebattery" with a cost factor of 10 produces a hash like "$2b$10$N9qo8uLOickgx2ZMRZoMy..." — notice that hashing the exact same password again produces a completely different-looking hash string each time, since bcrypt automatically generates a new random salt for every hash, yet verification still correctly matches any of them against the original password.
A common point of confusion is expecting to hash the same password twice and get an identical result, the way a simple hash function like SHA-256 would — bcrypt intentionally includes a random salt embedded within the output hash specifically to prevent identical passwords from producing identical hashes, which defends against precomputed "rainbow table" attacks; this is expected, correct behavior, not a bug. Another important consideration is the cost factor (rounds): a higher value makes hashing (and therefore brute-force cracking) significantly slower, but also increases the legitimate computational cost each time your own application verifies a login — most current recommendations suggest a cost factor of at least 10-12 for production systems, balanced against your server's available computational resources.
Tip: never use this tool (or any browser-based tool) as a substitute for your production application's actual authentication code — use it for learning, testing, and manual database work, but always let your real application generate and verify password hashes using a well-maintained bcrypt library within its own secure backend environment.