Cli tool to generate multisignatures

[girazoki]

What does it do?

It adds a tool to generate signatures, signers and encodings necessary to interact with the crowdloan module.

What important points reviewers should know?

Is there something left for follow-up PRs?

What alternative implementations were considered?

Are there relevant PRs or issues in other repositories (Substrate, Polkadot, Frontier, Cumulus)?

What value does it bring to the blockchain users?

Checklist

• Does it require a purge of the network?
• You bumped the runtime version if there are breaking changes in the runtime ?
• Does it require changes in documentation/tutorials ?

[crystalin]

@girazoki, Shouldn't we use polkadot binary for that ? As our relaychain is polkadot and the crownload is on polkadot, we probably shouldn't be the one providing the tools for it in our repo.

[girazoki]

the tool has a couple of purposes:

• First, generate a signature that allows a crowdloan contributor pass the verifier check in the crowdloan fund (This, as you said, is a Polkadot feature).
• Second, generate a signature of the native address that allows a crowdloan contributor to associate a native parachain identity (I see this as a moonbeam/parachain feature). This is necessary only if Add a memo field to crowdloan::contribute paritytech/polkadot#2613
  does not get accepted.

That being said, the latter can probably be done with polkadotjs/apps (I need to check whether the encoding is correct). The problem with the first case is that the signature needs to be an encoding of (fund_index, contributor, previous_amount_contributed, new_amount_contributed).

So is your suggestion to move this PR to Polkadot instead? Or use some binary that Polkadot does/will provide? I am not aware of the existence of such a binary, but maybe I missed it

[crystalin]

What worries me a bit is to include another signature type in our binary that might lead our users to misinterpret what Moonbeam support or also have them using the wrong signature by mistake

[girazoki]

We can have this in a private repository if that feels better

[girazoki]

Moved this to moonbeam-foundation/crowdloan-tools#1. The new repository is designed with the goal of having the app to generate the signatures too. If we agree, we can close this request