Several dependencies were copied over during the extraction of this
crate's logic from `zcash_primitives`, but are in fact only required for
the protocol-specific logic. We can also remove the `std` feature flag,
since we no longer have a dependency on `blake2b_simd` that needs its
`std` flag exposed for performance.
Previously we were returning the ciphertext as a slice, and then
asserting its length within the APIs the caller passed it into. Now
instead we require the caller to define whether or not the output is
compact, to make the API more predictable.
This doesn't place any additional constraints on users of this trait,
because the assertions already prevented a full output from being passed
to a compact trial decryption API.
`Domain::derive_esk` provides sufficient information to determine
whether or not we need to enforce `EphemeralSecretKey`-specific
decryption checks, as it returns `None` for pre-ZIP 212 notes.
`Domain::parse_note_plaintext_without_memo_ivk` is used with both full
note plaintexts and compact notes, so continues to accept a slice. For
all other `Domain` APIs, we constrain the input to `NotePlaintextBytes`
or `OutPlaintextBytes` as appropriate.
Requires patching three dependencies:
- bellman is pending a new release.
- nom is part of the funty breakage; we are blocking on a new release.
- orchard is in development.
Decrypted output size is `OUT_PLAINTEXT_BYTES`, which the decryptor
can always provide (either by decrypting into the correct size array
as now, or truncating the buffer before passing it to the domain).
This was left over from an earlier refactor where we could call a domain
API to extract cmstar from a note commitment (which could fail for
Orchard). This part of extraction was subsequently refactored into the
domain logic (and is rejected earlier for Orchard). The resulting bound
is wrong because it's always possible to serialize a scalar.
This change modifies note encryption and decryption functions
to treat a shielded output as a single value instead of handling
the parts of an output as independent arguments.
Jack Grigg
jarys
Kris Nuttycombe
Daira Hopwood
Kris Nuttycombe
Kris Nuttycombe