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Shamir Secret Sharing

Split a password or seed phrase into shares so any 3 of 5 (or any k of n) can rebuild it, with QR codes.

Free, no uploads, no sign-up. Runs 100% in your browser.

How Shamir Secret Sharing works

Each byte of the secret becomes the constant of a random polynomial over GF(256). Every share is one point on those polynomials. Any k points rebuild them exactly, and fewer than k say nothing at all about the secret. Random numbers come from the browser secure generator.

Output: TXT, QR.

How to use Shamir Secret Sharing

1. Open Shamir Secret Sharing and paste or type your input.
2. Results update instantly as you type.
3. Tweak options such as format, indentation or algorithm.
4. Copy the output or download it as a file.

Tips

• Everything is computed locally. Safe for tokens, keys and private data.
• Use Ctrl/⌘ + K to jump between developer tools quickly.

Shamir Secret Sharing FAQ

Are my files uploaded?

No. This tool runs entirely in your browser tab. Files are read from your disk into memory and the result is generated locally.

Is it free? Are there limits or watermarks?

Free and open source (MIT). There are no file-size caps, daily quotas, accounts or watermarks.

Does it work offline?

Yes, once the page (and any engine it needs) has loaded, it keeps working without a connection thanks to the service worker cache.

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