Electrum’s newest safety replace fixes a Lightning backup defect, however some Bitcoin pockets customers nonetheless want to exchange saved backups.
Older backups from wallets with non-deterministic Lightning keys lack data wanted to reclaim funds from anchor channels, a Lightning channel kind, after a distant shut.
Model 4.8.2, dated Sept. 11, stays the newest launch listed on Electrum’s official web site as of Oct. 1.
The person-backup repair provides payment-key data wanted to assert the person’s stability from an anchor channel closed by the peer. With out that data, an affected backup lacks the important thing wanted to comb the output, which means declare the cash on the Bitcoin blockchain.
Which wallets want consideration?
Electrum’s launch notes outline two situations that should coincide: the pockets has non-deterministic Lightning keys, and the backup issues an anchor channel.
Non-deterministic keys can’t be recreated from the pockets’s seed. The warning covers particular person channel exports and exported full-wallet backups regarding Lightning restoration.
Lightning wallets based mostly on BIP39 seeds or imported prolonged non-public keys (xprvs) at all times have non-deterministic Lightning keys. Electrum-seed wallets differ: their Lightning keys are deterministic when the pockets file was created in model 4.1 or later. Recordsdata created in 4.0.x don’t qualify merely as a result of the software program is now newer.
On desktop, pockets data marks the Lightning channels as non-recoverable from the seed, whereas the channel-opening dialog warns {that a} channel can’t be recovered from the seed on Android. Anchor-channel use stays the extra situation for this backup defect.
The person-backup repair additionally hides the choice to request a distant force-close when the backup can not sweep the ensuing output. The restriction retains that backup from requesting an in depth whose output it can not declare.
PR 10851 repairs wallet-file exports by retaining a randomly generated Lightning non-public key that the export beforehand deleted. Maintainer SomberNight explains that re-enabling Lightning in such a backup would generate completely different keys, leaving its older channel-backup data inadequate to spend anchor-channel funds.
An improve modifications the software program that produces and reads backups. Electrum’s documented treatment subsequently requires contemporary exports, and affected wallets show a startup warning.
The substitute step will depend on retaining the unique pockets knowledge wanted for a contemporary export. Putting in newer software program doesn’t assure restoration of key materials already misplaced with that knowledge.
