The kinds of operations we can perform with a Wallet instance depend on
whether or not we have access to the wallet's private key.
In order to differentiate between Wallet instances that know their private key
and those that do not, we use the WalletUnlocked and Wallet types
respectively.
The WalletUnlocked type represents a wallet whose private key is known and
stored internally in memory. A wallet must be of type WalletUnlocked in order
to perform operations that involve signing messages or
transactions.
You can learn more about signing here .
The Wallet type represents a wallet whose private key is not known or stored
in memory. Instead, Wallet only knows its public address. A Wallet cannot be
used to sign transactions, however it may still perform a whole suite of useful
operations including listing transactions, assets, querying balances, and so on.
Note that the WalletUnlocked type provides a Deref implementation targeting
its inner Wallet type. This means that all methods available on the Wallet
type are also available on the WalletUnlocked type. In other words,
WalletUnlocked can be thought of as a thin wrapper around Wallet that
provides greater access via its private key.
A Wallet instance can be unlocked by providing the private key:
let wallet_unlocked = wallet_locked.unlock(private_key); A WalletUnlocked instance can be locked using the lock method:
let wallet_locked = wallet_unlocked.lock(); Most wallet constructors that create or generate a new wallet are provided on
the WalletUnlocked type. Consider locking the wallet with the lock method after the new private
key has been handled in order to reduce the scope in which the wallet's private
key is stored in memory.
When designing APIs that accept a wallet as an input, we should think carefully
about the kind of access that we require. API developers should aim to minimise
their usage of WalletUnlocked in order to ensure private keys are stored in
memory no longer than necessary to reduce the surface area for attacks and
vulnerabilities in downstream libraries and applications.