The wallet now only stores Sapling extended spending keys, and thus can
only be used with keys generated from an HDSeed via ZIP 32.
Note that not all Sapling keys in the wallet will correspond to the
wallet's HDSeed, as a standalone Sapling xsk can be imported via
z_importkey. However, it must have been generated from a seed itself,
and thus is more likely to be backed up elsewhere.
This could in future be refactored to be generic over PaymentAddress and
NotePlaintext in the return type, but for now let's be explicit about which
returned notes are for Sprout vs Sapling, and handle them separately.
Co-authored-by: Sean Bowe <ewillbefull@gmail.com>
We need separate functions for checking Sprout and Sapling nullifiers,
because they are in separate domains and aren't guaranteed to be
collision-resistant (otherwise there is a possibility of a nullifier
collision, however remote, between Sprout and Sapling causing the spend
of one to prevent the spend of the other).
libzcash::PaymentAddress has been renamed to libzcash::SproutPaymentAddress,
and a new typedef boost::variant is now libzcash::PaymentAddress. Similarly
for ViewingKey and SpendingKey.
A new class InvalidEncoding is introduced as the default boost::variant
option for each address and key type; it is used during decoding instead
of boost::optional.
All address and key storage functions in the wallet have been modified to
refer specifically to the Sprout types, as they are used very precisely.
In most other cases, the more general type is leveraged as much as possible,
and we convert to the Sprout type when necessary. This will be subsequently
wrapped in, or replaced with, context-specific functions once Sapling
types are implemented.
Duke Leto
DenioD