[ADP-3350] Add Read.ChainPoint

[HeinrichApfelmus]

This pull request adds a data type ChainPoint to the Cardano.Wallet.Read hierarchy.

In order to add this type, we also need to

• Add functions related to hashing. The Cardano.Crypto.Hash.Class provides a very thoughtful API, we re-export it.
• Add a type RawHeaderHash that is an era-independent string of bytes representing a HeaderHash.

Comments

• This ChainPoint type is meant to be consistent with the other types in the Cardano.Wallet.Read hierarchy, which are in turn meant to be consistent with the ledger specification.
• The ledger specification stipulates that SlotNo ~ Natural. We stick to this type.
• The goal is to eventually remove the old primitive types.

Issue Number

ADP-3350

[paolino]

LGTM

[paweljakubas]

this one could be exported from cryptography-primitive lib

[HeinrichApfelmus]

(See the other comment.)

[paweljakubas]

what about exporting from here https://github.com/cardano-foundation/cardano-wallet/blob/master/lib/crypto-primitives/src/Cryptography/Hash/Blake.hs ?

[HeinrichApfelmus]

I sympathize, but the problem is that Cardano.Crypto.Hash.Blake2b does not re-export from cryptonite — rather, it defines a distinct type Blake2b_256 here:

https://github.com/IntersectMBO/cardano-base/blob/4e1d652343b48d3f02f05601e059b87965504e13/cardano-crypto-class/src/Cardano/Crypto/Hash/Blake2b.hs#L24

We will have to unify / merge in re-export the APIs at some point. At the moment, I think that the high-level API design of the cardano-crypto-classes is superior to cryptonite, but it covers only those algorithms and use cases that are needed by Cardano.

[paweljakubas]

👍