Module refresh 

Refresh Shares

Refreshing shares has two purposes:

• Mitigate against share compromise.
• Remove participants from a group.

Refer to the FROST book for important details.

This modules supports refreshing shares using a Trusted Dealer or DKG. You probably want to use the same approach as the original share generation.

For the Trusted Dealer approach, the trusted dealer should call compute_refreshing_shares() and send the returned refreshing shares to the participants. Each participant should then call refresh_share().

For the DKG approach, the flow is very similar to DKG itself. Each participant calls refresh_dkg_part_1(), keeps the returned secret package and sends the returned package to other participants. Then each participants calls refresh_dkg_part2() and sends the returned packages to the other participants. Finally each participant calls refresh_dkg_shares().

Functions

compute_refreshing_shares

Compute refreshing shares for the Trusted Dealer refresh procedure.

refresh_dkg_part2

Performs the second part of the refresh procedure for the participant holding the given round1::SecretPackage, given the received round1::Packages received from the other participants.

refresh_dkg_part_1

Part 1 of refresh share with DKG.

refresh_dkg_shares

Performs the third and final part of the refresh procedure for the participant holding the given round2::SecretPackage, given the received round1::Packages and round2::Packages received from the other participants.

refresh_share

Refresh a share in the Trusted Dealer refresh procedure.