Shamir's Secret Sharing
Split a secret into shares and recombine them to recover it.
Shamir's Secret Sharing splits a secret so that a chosen number of shares are needed to recover it. All computation runs in your browser and nothing is uploaded.
100% private - runs entirely in your browser.
Your input, keys and passwords are never uploaded. Want proof? Load this page, then turn off your internet - the tool still works. For an exact check, open your browser's DevTools Network tab and confirm no data is sent when you use it.
About the Shamir's Secret Sharing
Split a secret into several shares so that a chosen number of them (the threshold) are needed to recover it, and fewer reveal nothing.
This is useful for backing up keys or passwords across people or devices without trusting any single one.
All computation uses finite-field math in your browser, and nothing is uploaded.
Key features
- Split into up to 255 shares
- Set how many are needed to recover
- Combine shares to rebuild the secret
- Runs entirely in your browser
How to use
- 1Enter the secret, total shares and threshold.
- 2Give one share to each holder.
- 3Later, paste any threshold of shares to recover the secret.
Examples
a secret, 5 shares, threshold 35 hex sharesAny 3 of the 5 can rebuild the secret.
any 3 of the sharesthe original secretFewer than the threshold reveal nothing.
Frequently asked questions
- How does the threshold work?
- If you split into 5 shares with a threshold of 3, any 3 shares rebuild the secret, but 2 or fewer reveal nothing about it.
- What can I split?
- Any text secret, such as a password, recovery phrase or private key.
- Is my secret uploaded?
- No. Splitting and combining run entirely in your browser.