Strong Password Generator

The Strong Password Generator creates cryptographically random passwords using the browser's native Web Cryptography API (window.crypto.getRandomValues()), the same entropy source used by operating systems for TLS key generation and full-disk encryption. Unlike passwords produced by Math.random() — which is a deterministic pseudo-random number generator (PRNG) seeded from predictable values — window.crypto.getRandomValues() draws from the OS-level hardware random number generator (HRNG), producing passwords with maximum unpredictability. The tool supports configurable character sets (uppercase A–Z, lowercase a–z, digits 0–9, and 32 printable symbols), variable length (8–128 characters), and displays a real-time password entropy strength meter measured in bits.

Algorithmic Logic & Calculation

The generator builds a character pool from the selected character sets (uppercase: 26, lowercase: 26, digits: 10, symbols: 32). It calls crypto.getRandomValues() to fill a Uint32Array with n cryptographically secure random 32-bit integers, where n equals the desired password length. Each integer is then reduced modulo the pool size (random_int % pool.length) to select a character, eliminating modulo bias by using rejection sampling when the pool size does not divide evenly into 2^32. Password entropy (in bits) = log₂(pool_size^length) = length × log₂(pool_size), displayed on a color-coded strength gauge.