ZBC is never burned
Many blockchains destroy coins, as a penalty or to make the remaining coins scarcer. From version 0.5.8 no ZooBC rule destroys ZBC. What another chain might burn goes to the longevity pool instead, and from there to the nodes that keep doing the work.
Where burned coins would go
Three kinds of ZBC end up in the longevity pool rather than being destroyed:
- Stake penalties. A node's locked stake carries 10 % at risk. That 10 % goes to the longevity pool when the node is expelled because its score reached zero, when it exits while missing or suspended, when it leaves the queue, and when it is dropped from the queue for missing its attendance (leaving the registry, queue). A node that exits in good standing gets its whole lock back.
- Attendance fees. A queued node that shows no other sign of life in a daily window sends a QueueAttendance transaction, whose fee comes out of its stake; that fee goes to the longevity pool too (queue).
- Dust. When an account's balance cannot cover its rent, the account is pruned and the small balance left in it goes to the longevity pool. The same happens to the balance of an account group that is dissolved (account rent and pruning).
Fees are not burned either: they go to the reward pool of their block and the coinbase lottery (fees).
Back to the nodes
The longevity pool pays out a slice in every block through the coinbase lottery (pools). A penalty therefore ends up rewarding the nodes that keep producing and relaying, in proportion to their participation score. Nobody receives it directly: not the treasury, not the ZooBC Foundation, and not the account that paid it, which gets nothing back later.
Lost keys
Coins in an account whose key is lost are not stranded for ever. The account keeps paying its rent until its balance cannot cover the next payment; then it is pruned and its dust goes to the pool. The coins return to circulation through the nodes, and no ZBC is lost.
Other assets can be burned
The rule is about ZBC. ZBC is not a token, and no token transaction can mint or burn it. Other assets can be destroyed:
- a user token issued as redeemable can be burned with BurnToken, which pays the burner its share of the token's ZBC backing (minting and burning tokens);
- a wrapped bridge coin is burned from the custody account when it is withdrawn to its home chain (bridge and wrapped coins).
The chain keeps a tally of burned assets. It counts those burns, and its total for ZBC stays at zero.