Module refresh 

FROST Proactive Secret Sharing — share refresh without changing the group key.

Allows participants to refresh their key shares periodically to limit the window of compromise. After refresh, old shares become useless but the group public key remains unchanged.

Protocol

Each participant generates a zero-secret polynomial (constant term = 0) of degree (t-1), evaluates it at each other participant’s identifier, and distributes the “refresh deltas”. Each participant adds all received deltas to their existing share.

Because the constant term is zero, the group secret s = f(0) is unchanged.

Structs

RefreshPackage

A refresh package from one participant to distribute refresh deltas.

Functions

apply_refresh

Apply refresh deltas to an existing key package.

generate_refresh

Generate a refresh package for proactive share refresh.

verify_refresh_package

Verify that a refresh package is valid (zero-secret invariant).