Bcrypt Hash Generator & Verifier
Hash a password with Bcrypt, or check a plaintext password against an existing hash
Bcrypt is a key-stretching algorithm built specifically for password storage. This tool generates Bcrypt hashes and checks whether a plaintext password matches an existing hash — all in your browser, so nothing you type is ever sent to a server.
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🔒 Everything runs 100% in your browser. Your files and input are never uploaded to any server.
How to use
- Pick the Generate or Verify tab.
- To generate: enter your password, choose the Blowfish revision ($2b$) and the cost factor (default 10), then hit Generate.
- To verify: paste the plaintext password along with the stored $2b$... Bcrypt hash, then hit Verify.
- Watch the live progress bar (0%–100%) and read off the resulting hash.
FAQ
- What does the cost factor do?
- It's the base-2 logarithm of the number of hashing rounds, so it sets how expensive the algorithm is to run. Every +1 doubles the work, which is what makes brute-force attacks impractical.
- Is the output compatible with real Bcrypt libraries?
- Yes. The tool runs the Blowfish rounds asynchronously on top of the browser's Web Crypto API using a spec-compliant implementation, so the salt and hash it produces follow the standard Bcrypt format.
- Why does hashing the same password twice produce a different hash each time?
- Bcrypt generates a fresh random salt for every hash and embeds it in the result, so the same password always yields a different hash string. During verification, the salt stored inside the hash is reused automatically, so the match check still works correctly.