How to use the Bcrypt Hash Generator
Hash: Enter a password, choose the cost factor (rounds), and click Generate. Higher rounds = slower = more secure.
Check: Switch to Verify mode, enter the original password and the bcrypt hash, and click Verify to confirm they match.
What is it?
Bcrypt is an adaptive password hashing algorithm designed by Niels Provos and David Mazières in 1999. Unlike SHA or MD5, bcrypt is intentionally slow and has a configurable cost factor (rounds) that determines how computationally expensive the hash is. This makes brute-force and rainbow table attacks impractical.
Each bcrypt hash includes the cost factor and a random 128-bit salt, so the same password produces a different hash every time. The standard recommendation is 10–12 rounds for web applications (balancing security and response time). All hashing runs entirely in your browser — your password is never transmitted.
Benefits
Verify data integrity instantly
Hash comparison confirms whether a file, API response, or downloaded binary has been altered in transit or at rest — without storing the original content.
Authenticate requests and webhooks
HMAC signatures prove a request came from a trusted source and was not modified in transit — the mechanism behind Stripe, GitHub, and AWS webhook security.
Protect sensitive data at rest
AES-256 encryption makes stored content unreadable to anyone without the key — even if your database, S3 bucket, or file system is fully compromised.
Generate credentials that meet security standards
Cryptographically random output from the Web Crypto API satisfies NIST entropy requirements — unlike predictable Math.random()-based alternatives.
Frequently asked questions
Why is bcrypt better than SHA256 for passwords?
SHA256 is designed to be fast — a GPU can compute billions per second. Bcrypt is designed to be slow and configurable. At 12 rounds, bcrypt takes ~250ms per hash, making brute force attacks millions of times harder.
What cost factor (rounds) should I use?
12 is the current recommended default. Each increment doubles the work: 12 rounds takes ~2x longer than 11. Adjust so that hashing takes 250–1000ms on your production server.
Why does the same password produce a different hash?
Bcrypt automatically generates and embeds a random 128-bit salt in each hash. This prevents rainbow table attacks and means two identical passwords will never produce the same hash.