I would like to know if Hyperledger Fabric does support use of custom signatures?
If so, can you point me to some documentation?
I tried to find out if it is possible to use schnorr signature in Hyperledger Fabric. I couldn't find anything useful in the documentation, however.
Technically it is possible but it would require code changes to Fabric itself to support a different signature algorithm. For example, this code change implements ed25519 for Fabric:
https://github.com/hyperledger/fabric/pull/3343
Some time ago, there was a proposal to rearchitect the crypto implementation in Fabric to make it more easily pluggable. I don't know of any work to actually make this happen.