Yes, 100% safe. Our analyzer works entirely in your browser. We never send your password to our servers. For breach checking, we only send the first 5 characters of the SHA-1 hash (using k-anonymity) to the Have I Been Pwned API.

zxcvbn (developed by Dropbox) uses pattern matching and realistic password cracking simulations. It detects:

• Common words and their l33t speak variations
• Keyboard patterns (qwerty, 123456)
• Dates, years, and sequences
• Repeat and spatial patterns
• Dictionary words in multiple languages

Unlike basic checkers that only count character types, zxcvbn models real attacker behavior.

The crack time estimation is based on:

• 10,000 guesses per second (offline attack with slow hashing)
• Current computing capabilities
• Password entropy and pattern analysis

While actual crack times vary based on attacker resources, our estimates are conservative and realistic for sophisticated attacks.

YES, immediately. If your password appears in any breach database:

1. Change it on all accounts where you've used it
2. Enable two-factor authentication where available
3. Use our generator to create a new, unique password
4. Consider using a password manager for better security

Breached passwords are often sold on dark web markets and used in credential stuffing attacks.