Rln-Relay: Persisting rln credentials

[staheri14]

In the dynamic/onchain mode of waku rln relay, generated rln credentials are not being persisted. As such, the wakunode create, registers, and uses a new set of credentials for each run. While this does not cause a serious problem during dogfooding on a testnet, it causes fund loss due to unnecessary re-registration to the group.
This issue is to implement necessary mechanism to properly persist and resue rln credetnials across multiple runs.

[kgrgpg]

@staheri14 You can track the pull request associated with this issue here:
#1037

[staheri14]

The nimbus key-store is a potential solution for this problem.
Might be useful to have a look at https://github.com/status-im/nimbus-eth2/blob/88532c61772ed8c065fe7ab2e9204a8c40de4656/tests/test_keystore_management.nim

[LNSD]

As @staheri14 has pointed out, the idea is to use the same Keystore implementation as nimbus uses.

• Sources:
  • https://github.com/status-im/nimbus-eth2/blob/stable/beacon_chain/spec/keystore.nim
  • https://github.com/status-im/nimbus-eth2/blob/stable/beacon_chain/validators/keystore_management.nim
• Tests:
  • https://github.com/status-im/nimbus-eth2/blob/stable/tests/test_keystore.nim
  • https://github.com/status-im/nimbus-eth2/blob/stable/tests/test_keystore_management.nim

At first, seems that depends on nimbus-specific types (e.g., beacon_chain/spec/datatypes/base). Some of those types might be interesting to port also into nwaku codebase.

Added to that, I foresee that @s1fr0 review will be very valuable during this code porting/integration.

[arnetheduck]

Of (design) interest here might be clef - that said, it would indeed be good to keep key management coherent within our suite of apps - exporting the keystore from nimbus is certainly possible cc @zah

[s1fr0]

With the implementation of Web3 Secure Storage keyfiles, merged with #1285, this issue can be closed.