Integrate the Mithril Crypto

[perturbing]

To make the KES agent sign data that the Mithril node needs, we need to add an interface that lets us sign this data with the mlocked key in memory. This includes two data packets as defined here.

[perturbing]

Given that Leios also will depend on BLS signatures (as mithrill does). There is an argument to be made to implement this properly in cardano-base. That is, create bindings and a proper interface + utility functions for these.

[perturbing]

That is, create bindings and a proper interface + utility functions for these.

This work can be tracked here IntersectMBO/cardano-base#548

[perturbing]

The above cardano-base PR now implements via BLST bindings

• Basic secure key generation
• Sign and verify functionality
• And a general interface for Proof of Possession (as per the IETF draft)
• Tests for all of the above

TODO

• Add external test vectors of POP and singatures
• Add batch verification for bls signatures using the fast blst bindings