Arkworks serialization wrapped in Parity SCALE codec

ArkScale(T) can be serialized or deserialized using parity-scale-codec, provided T can be serialized or deserialized using ark-serialize.

Arkworks serializes via the std::io::{Read,Write} traits, or its no_std fork of those traits, as do other zcash sapling derivatives. At its core, Parity SCALE codec also consists of traits {Input,Output} analogous to std::io::{Read,Write} respectively, as well as traits {Decode,Encode} also quite similar to ark-serialize::{CanonicalDeserialize,CanonicalSerialize}. We simply translate between these extremely similar traits, including wrapping and unwrapping errors appropriately.

ArkScale cannot easily implement MaxEncodedLen or ConstEncodedLen from SCALE, due to the orphan rules. You'll need these if using weights in Frame, so you should usually create wrapper types around ArkScale. As a rule, anytime you choose curves then you'll have a conditionanl ark-substrate dependence anyways, so wrapper types should not become too onerous, and they likely improve documentation, errors, etc anyways.

ArkScale panics if serialization fails because SCALE does not propogate serialization failures. ArkScale users should therefore be responcible for ensuring T: CanonicalSerialize cannot fail for mathematical reasons, at least when using ArkScale in Polkadot. In principle, any serialization code could fail from memory exaustion, but Frame avoids this, provided you've set MaxEncodedLen correctly on your wrapper types.