Random Byte Generator
Choose up to 4,096 bytes and receive a local byte list or binary file. This page uses crypto.getRandomValues when the browser provides it.
A QUICK WALKTHROUGH
How to use this tool
- Choose a byte count and an output format.
- Generate the bytes locally with the browser Web Crypto API.
- Copy the list or download the exact bytes as a binary file.
Bounded local output
The generator accepts 1–4,096 bytes per request and keeps the result in this page until you copy or download it. It does not upload, store, or transmit the generated values.
Cryptographic randomness and browser limits
When available, crypto.getRandomValues provides cryptographically strong random bytes suitable for nonces, test fixtures, and development values. The browser and operating system supply the randomness; this page cannot independently prove the quality of that source. Browsers may restrict Web Crypto in insecure contexts, private modes, or unusual embedded environments, and this tool stops with an error instead of using a weaker fallback.
GOOD TO KNOW
Common questions
Are these bytes cryptographically secure?
They are generated with crypto.getRandomValues, the browser Web Crypto API intended for cryptographically strong random values. Protect the output and choose a dedicated secret-management process for production credentials.
What is the maximum output?
One request is limited to 4,096 bytes so the list, copy action, and download remain bounded in the browser.
Does the binary file contain text?
No. The binary download contains the raw byte values. The on-page list is only a display format.
Why can generation fail?
Some browsers or embedded contexts do not expose Web Crypto, or restrict it outside a secure context. The tool reports that limitation and never falls back to predictable Math.random values.