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Neptune-Crypto / neptune-core

anonymous peer-to-peer cash
Apache License 2.0
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Store incoming randomness and restore wallet balance from disk #23

Closed Sword-Smith closed 1 year ago

Sword-Smith commented 1 year ago

It's not enough to store incoming and outgoing randomness in the DB, as this is cryptographic data without which funds might be lost. As the DB schema changes, this randomness can get lost if it's not also written to disk in the files incoming_randomness.dat and outgoing_randomness.dat found in <data_dir>/<network>/wallet.

For each incoming/outgoing transaction, we probably want to store the randomness as well as the block height and block digest in which the UTXO was mined. Then recovering the membership proofs and populating the wallet DB should not be too hard.

aszepieniec commented 1 year ago

I'm a little confused. Please elaborate.

Sword-Smith commented 1 year ago

If you're running an archival node everything that's needed to restore an MSMP (with an empty wallet DB) should be stored in separate files, not only in the database.

Sword-Smith commented 1 year ago

Storing sender randomness and AOCL index should be sufficient. From this data, the mutator set membership proof can be restored.

Sword-Smith commented 1 year ago

ArchivalMutatorSet has a method called restore_membership_proof that we can call on startup. The new data structure IncomingUtxoRecoveryData contains the data needed. The function to restore the database should probably be implemented as a method on GlobalState since it will read data from both the wallet and the archival state.

This function should take the digest of the block tip, maybe as a lock on LightState, and then see if it can find a matching MonitoredUtxo in the database for each IncomingUtxoRecoveryData instance. If it cannot, it can generate a new MonitoredUtxo from the IncomingUtxoRecoveryData and the ArchivalMutatorSet and then insert this into the wallet DB.

Sword-Smith commented 1 year ago

With e1327631512d3ddc90947870871f27affca62ed7, we can now restore monitored UTXOs/the wallet database from disk.

Storing outgoing randomness can be handled through another issue. Closing this as completed.