BLS signatures and aggregation

[joebebel]

Hopefully we can identify a suitable existing implementation, otherwise implement independently.

Any implementation should take into account the issues described here

https://ethresear.ch/t/fast-verification-of-multiple-bls-signatures/5407

NuBLS is a pure rust implementation, but of course the dependencies are an issue.
blstrs - another option, dependency issues and also depends on unsafe code/C library

https://www.cc.gatech.edu/~aboldyre/papers/bold.pdf

[joebebel]

It is worth noting that BLS signatures are needed for distributed key signing, but potentially not for DKG participant signatures (another signature scheme could be used).

[joebebel]

Unfortunately BLS signatures are not directly compatible with the PVSS/PVDKG, so we'll have to put this on ice until we have a need for it.