FREE · SECURITY & PRIVACY TOOLS
Shamir Secret Sharing.
Split a password, recovery phrase or key into several shares so that any chosen number of them can rebuild it, and recover it again — entirely in your browser.
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How to use Shamir Secret Sharing
Enter the secret, the number of shares and how many are needed, then press “Make new shares”. To recover, switch to Recover and paste enough shares.
How it works
Shamir’s scheme over GF(256): each byte is the constant term of a random polynomial of degree k − 1 (random coefficients from the browser’s secure generator); recovery uses Lagrange interpolation at zero.
Example
“correct horse battery staple” split into 5 shares with a threshold of 3 can be rebuilt from any 3 shares; 2 shares reveal nothing.
Questions about Shamir Secret Sharing
Is Shamir Secret Sharing free, and do I need an account?
Yes. This tool is free to use in your browser without an account. Processing takes place on your device.
What are the limits and what should I check?
Up to 4,096 bytes and 255 shares. A damaged share gives a wrong result without warning: test recovery once. Everything is calculated in your browser; nothing you type is uploaded. Review the result before using it in your work.
Is my input sent to a server?
Your input is processed in your browser and is not uploaded by this tool. Files and pasted text are cleared when the page is refreshed. Normal website requests are still required to load the page and its libraries. Read the privacy explanation.