SwipeChain actively churns its validator set to prevent stagnation and capture, and ensure liveness in signing committees. Churning is also the mechanism by which the SwipeNode software can safely facilitate non-contentious upgrades.
Every 50000 blocks (3 days) SwipeChain will schedule the oldest and the most unreliable node to leave, and rotate in two new nodes. The next two nodes chosen are simply the nodes with the highest bond.
During a churn event the following happens:
The incoming nodes participate in a TSS key-generation event to create new Asgard vault addresses
When successful, the new vault is tested with a on-chain challenge-response.
If successful, the vaults are rolled forward, moving all assets from the old vault to the new vault.
The outgoing nodes are refunded their bond and removed from the system.