Shamir Secret Sharing

Shamir secret sharing in the browser

Adi Shamir's threshold scheme splits a secret into N shares so any K shares reconstruct the secret, but fewer than K reveal nothing (information-theoretic threshold in the ideal model). This tool uses polynomial interpolation over a 127-bit prime field, entirely client-side.

Split and combine

1. Choose split mode, set total shares N and threshold K (2 ≤ K ≤ N).
2. Enter the secret and distribute share blocks to custodians.
3. In combine mode, paste at least K share blocks separated by blank lines to recover the secret.

For transport encryption of shares, combine with RSA Sign Verify or your organization's key-management process.