Secure Random Generator

It means the numbers are generated by the Web Crypto API (crypto.getRandomValues()), the same secure source browsers use for TLS keys and session tokens. Unlike Math.random(), its output is unpredictable and suitable for passwords, keys, lottery-style draws, and other security-sensitive uses. It cannot be guessed or reproduced even if an attacker knows the algorithm and previous outputs.

Math.random() is a fast pseudo-random generator designed for simulations and games — it is deterministic and, in principle, predictable. crypto.getRandomValues() pulls entropy from the operating system's cryptographic random number generator and is designed to be unpredictable. For anything involving security — passwords, tokens, keys, draws where money or access is at stake — you should use the cryptographic source, as this tool does.

A naive "value % range" approach introduces modulo bias: some outcomes occur slightly more often than others. Rejection sampling discards values that fall into the biased tail and only accepts uniform samples, so every integer in your chosen range is exactly as likely as every other. The difference is tiny for small ranges but matters for security-sensitive uses and for large ranges.

Yes. All generation runs locally in your browser using the built-in Web Crypto API, so no data is sent anywhere and no network connection is required. The tool works fully offline after the page loads, which is also why it is completely private — random values are produced on your device and never transmitted.

You can generate up to 100 values per batch in any mode. For tokens and hashes you can also adjust the length (bytes or characters). Because the Web Crypto API is hardware-accelerated in most browsers, generating hundreds of values takes only milliseconds.

Yes — completely free, no registration, and 100% private. Random values are produced locally in your browser using the platform's secure random generator and are never sent to a server. The tool works offline and stores nothing.