Following the previous commit, some external hardware signers require a
master key fingerprint to be present within the PSBT input derivation
paths so that the signer can recognize which inputs are relevant and
must be signed.
For key scopes which have an address schema where the external and
internal branches differ, we always assume that imported keys use the
external address type defined in the scope's address schema. This may
not always be the case however, and should be handled correctly.
Ideally, we generate two addresses per imported key (only if the
external and internal address types differ) and scan for both in the
chain.
This change was motivated by the need to support importing BIP-0049 keys
that use the standard address derivation scheme, where nested witness
pubkeys are used for both the external and internal branches. Our
BIP-0049 key scope is slightly different, in that addresses derived from
the internal branch use the witness pubkey address type. By having the
option of overriding the address schema for a particular account, we can
support importing standard BIP-0049 keys.
The master fingerprint corresponds to the fingerprint of the root master
public key (otherwise known as m/). This is required by some hardware
wallets for proper identification and signing.
The address schema is an optional field that allows an account to
override its corresponding address schema with a custom one.
Watch-only accounts are usually backed by an external signer as they do
not contain any private key information. Some external signers require a
root key fingerprint for identification and signing purposes. In order
to guarantee compatibility with external signers, we need to persist the
root key fingerprint within the database.
Before this change, watch-only accounts used the default account
database structure. In this commit, we introduce a new account type to
store different information for watch-only accounts only. This isn't a
breaking change as watch-only accounts have yet to be supported by the
primary user of the wallet (lnd). With this new account type, we can
avoid the empty private key fields, which are irrelevant to watch-only
accounts, and we can store the root key fingerprint.
Previously, addresses that belong to a watch-only account would have a
derivation path using the internal account number used to identify
accounts within the databse, rather than the actual account number based
on the account's master public key child index. This wasn't an issue
before as only one account would exist within the wallet, the 0 account,
which is also the default. To ensure users of the DerivationPath struct
can arrive at addresses correctly, we introduce a new field
InternalAccount to denote the internal account number and repurpose the
existing Account field to its actual meaning.
This PR allows the creation of managers and accounts that are watch-only. The state of the database after creation would be identical to the state after calling
Manager.ConvertToWatchingOnly, assuming accounts with the right xpubs were created in the former case.
Co-authored-by: Ken Sedgwick <ken@bonsai.com>
Due to a no longer existing bug within the wallet, it was possible for
change addresses to be created outside of their intended key scope (the
default), so wallets affected by this now need to ensure they scan the
chain for all addresses within the default key scopes (as expected), and
all _internal_ addresses (branch used for change addresses) within any
other registered key scopes to reflect their proper balance.
This commit makes nextAddresses add a function to the transactions
OnCommit handler used to update the cache on successful database
transaction commit. Before this we would risk the cache and database of
get out of sync if the database transaction failed or was aborted after
the cache was updated.
In this commit, we add the new DerivationInfo method to the current
default implementation of the ManagedPubKeyAddress interface. In doing
this, we replace the account field with the derivationPath, as we can
obtain the account field from the derivationPath itself.
This commit resolves a deadlock observed when attempting
to generate addresses. There were a few cases, particularly
in chainAddressRowToManaged and loadAccountInfo, which accessed
the public IsLocked() method of the Manager, even though the
shared mutex had already been acquired.
The solution is to create an internal isLocked() method, which
can be safely called assuming the manager's mutex has already been
acquired. As the comments above both of the methods in question
specify, we can assume the Manager's mutex *is* already acquired.
This commit also reduces some unnecessary code duplication, since
the recent changes left both a Locked() and IsLocked() method that
perform the same functionality. IsLocked() was favored as it more
clearly indicates that the returned value is a boolean.
In this commit, we create a new struct that houses the key derivation,
address management, and account management for a particular scope. A
scope consists of a (purpose, cointype) tuple. Additionally, each
ScopedKeyManager is able to generate internal/external addresses for a
specific *address type*. This make rescans easier as for each scope, we
know what type of output to look for within the chain.
The ScopedKeyManagers have two new primary methods that weren’t
previously present within the regular Manager:
* DeriveFromKeyPath
* NewRawAccount
These two methods allow callers a greater degree of control over the
way that accounted are created and addressed derived.
In this commit, we introduce the concept of scopes for individual key
managers. Each scope will lock down a key manager to a particular
purpose and coin type within the BIP0043 hierarchy. Each scope will
also have a set address type schema. This schema will be consulted when
creating addresses for a particular scoped key manager.
Finally, we introduce 3 new default scopes:
* BIP 44
* BIP 84
* BIP 49++ (BIP49 but uses p2wkh for change addresses)
