CryptoGuard

password strength analyser · v0.3.1

Your password
deserves entropy.
Not guesses.

Shannon entropy + pattern heuristics + Have-I-Been-Pwned breach check via k-anonymity. Runs entirely in your browser — nothing leaves the client.

01101 0xAF 11010 SHA-1 73 bit 0x4E 01001 pbkdf2

Passphrase Analyser

Type below — computed live in your browser

SHA-1 · entropy · k-anon
—
crack time: —
Entropy
— bits
Charset Size
—
Length
—

Generate Passphrase

Cryptographically secure via SubtleCrypto

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How HIBP k-Anonymity Works

Only the first 5 hex chars of SHA-1 ever leave your device

1. Local: SHA-1(password) → AABBCCDDEE…
2. Send only first 5 chars: GET /range/AABBC
3. HIBP returns ~500 hash suffixes matching AABBC
4. Client checks if DDEE… is in the response
5. Password itself never transmitted
✓ Result: true zero-knowledge breach lookup

Production API endpoint: POST /api/v1/analyze with check_breaches:true. Full spec in GitHub README.