Cleanup Protocol

graph LR ms-->fb subgraph off-chain state fb["<b>Free Balance</b> (ETH) <br> Local Nonce: <tt>k + 1</tt> <br> Alice has 11 ETH <br> Bob has 9 ETH"] end subgraph on-chain state ms["<b>AB Multisignature Wallet</b> <br> Balance: 20 ETH"] end
NOTE: Notice that the stale-invalid state object has been removed from the previous figure shown in the Uninstall Protocol representing the effective “garbage collection” phenomena of the cleanup protocol

The cleanup protocol is a protocol that is periodically run to update the dependency of every active application to a newer root nonce version. In effect, it achieves the goal of O(1) constant time invalidation of outdated state put on-chain by resetting the state such that regardless of the number of historical / outdated apps that have been uninstalled, refuting their validitity on chain requires a single transaction.


sequenceDiagram Alice->>+Bob: CleanupInstall Bob-->>-Alice: CleanupInstallAck Alice->>+Bob: IncrementRootNonce Bob-->>-Alice: IncrementRootNonceAck
NOTE: The dependency in the message exchange is important; it is not safe to sign the root nonce commitment without possession of all the active app commitments.

The CleanupInstall Message

Field Description
protocol "cleanup"
fromAddress The address of Alice
toAddress The address of Bob
seq 0
signature Alice's signed commitment digest

The CleanupInstallAck Message

Field Description
protocol "cleanup
fromAddress The address of Alice
toAddress The address of Bob
seq 1
signature Bob's signed commitment digest


Commitments for CleanupInstall and CleanupInstallAck:

For each active application, a similar commitment to the one described in the Install Protocol must be generated. The commitment calls executeAppConditionalTransaction with a limit of c_1 + c_2 and a expected root nonce key of r + 1. Note that this is different from the install commitment in that it is not a multisend and does not set the free balance. Note that the free balance is also considered an active app. Here is an example of a commitment for a given app:

graph LR subgraph ConditionalTransaction executeAppConditionalTransaction executeAppConditionalTransaction.->REGISTRY executeAppConditionalTransaction.->NONCE_REGISTRY executeAppConditionalTransaction.->uninstallKey executeAppConditionalTransaction.->rootNonceKey executeAppConditionalTransaction.->rootKey["rootNonce (r + 1)"] executeAppConditionalTransaction.->appCfAddress executeAppConditionalTransaction.->terms end subgraph Multisig execTransaction-->executeAppConditionalTransaction end

Then, finally, the commitment update the root nonce is simply:

graph LR subgraph NonceRegistry setNonce setNonce.->rootNonceTimeout setNonce.->rootNonceSalt setNonce.->one["r + 1"] end subgraph Multisig execTransaction-->setNonce end