In this section, we'll cover the possible ways of recovering the funds within a Pool account upon data corruption/loss. Account funds are locked to a 2-of-2 multi-sig output of the account owner and the Pool auctioneer until the account's expiration has been met, giving the account owner full control of the funds. This expiration is included in the account output script, so it must be known in order to spend the account funds. There are two possible ways to recover an account's funds after data corruption/loss: one that requires the Pool auctioneer's cooperation, which is the only method currently supported, and one without, which will require storage of an additional data blob similar to the Static Channel Backups present within lnd. An auctioneer-assisted account recovery intent can be issued through the pool accounts recover command or the RecoverAccounts RPC.

$ pool accounts recover -h
NAME:
   pool accounts recover - recover accounts after data loss with the help of the auctioneer
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USAGE:
   pool accounts recover [arguments...]
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DESCRIPTION:
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  In case the data directory of the trader was corrupted or lost, this
  command can be used to ask the auction server to send back its view of
  the trader's accounts. This is possible as long as the connected lnd
  node is running with the same seed as when the accounts to recover were
  first created.
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  NOTE: This command should only be used after data loss as it will fail
  if there already are open accounts in the trader's database.
  All open or pending orders of any recovered account will be canceled on
  the auctioneer's side and won't be restored in the trader's database.

Auctioneer-Assisted Account Recovery

As part of the initial Lightning Pool launch, an account recovery method has been added that requires the cooperation of the auctioneer. This method is based on the account owner sending a recovery intent to the auctioneer, along with a challenge response to prove ownership. The recovery intent includes a set of keys derived by the same account BIP-0043 derivation path m/1017'/coin_type'/220'/0/index, so the same lnd seed that was to used to initially create the accounts must be used.

Upon the auctioneer receiving the intent, it will verify the challenge response, determine the validity of account key to recovery, and provide the account owner the latest details of the account known to the auctioneer. This allows the account owner to continue using their account within the auction without having to perform any on-chain transactions. As usual, the account owner can decide to close the account and withdraw their funds to their desired outputs if they no longer wish to participate in the auction.

Note that as a part of this process, all orders belonging to an account being recovered are canceled within the auction and are not restored to the account owner.