About Secure Password Generator & Entropy Analyzer
NIST SP 800-63B compliant password generator with real-time Shannon entropy calculation (in bits) and brute-force crack time estimates. Choose between full character combinations (uppercase, lowercase, digits, symbols), memorable Diceware multi-word passphrases, numeric PINs, or pronounceable strings. Includes NATO phonetic spelling guides and 1-click secure copying.
Key Capabilities & Features
- Web Crypto API CSPRNG hardware entropy generation
- Modes: All Characters, Memorable Diceware Passphrases, Numeric PINs, and Pronounceable
- Live Shannon entropy calculation: E = L * log2(poolSize) bits
- NIST SP 800-63B strength classification and supercomputer brute-force crack time estimates
- NATO phonetic spelling transcription for error-free verbal communication
- Visual eye toggle to mask or unmask passwords during screen sharing
How to Use Secure Password Generator & Entropy Analyzer
Choose Mode
Pick All Characters, Memorable Diceware, or PIN.
Adjust Length & Character Pools
Set length slider (6 to 64 chars) and toggle uppercase, symbols, or numbers.
Review Entropy & Strength
Inspect the Shannon bits rating (aim for 75+ bits for strong passwords).
Copy to Clipboard
Click copy to transfer directly into your password manager.
Privacy & In-Browser Execution Guarantee
100% Client-Side. Passwords are generated in browser volatile RAM and never transmitted across networks.
Frequently Asked Questions
Why are multi-word Diceware passphrases secure?
A passphrase like "correct-horse-battery-staple" is easy for humans to remember but contains 60 to 80 bits of entropy, making it virtually impossible for automated brute-force attacks to crack.
What is Shannon entropy in passwords?
Shannon entropy measures the amount of unpredictability in the password expressed in bits. Every additional bit doubles the number of guesses an attacker must attempt.
How is password entropy and estimated crack time calculated?
Entropy is computed using Shannon entropy formulas based on the active character pool size: E = L * log2(R). Estimated crack times assume an offline brute-force attack running at 100 billion guesses per second with multi-GPU rigs.