Extend Flexible Privacy feature to support Tessera's EC encryptor

[freemanzMrojo]

Description

As a user, I want to extend the Flexible Privacy feature so that I am able to use it along with Tessera's EC encryptor mode.

The Flexible Privacy feature relies on these Smart Contracts and the Java wrappers "above" them. As we can see, they expect a bytes32 argument for the participants (Tessera's enclave public key).

For the EC encryptor mode of Tessera, we expect enclave public keys to be longer than 32. This means that we need to somehow adapt the code so we can use these keys as identifiers of the participants as well. For instance, we could modify the contracts so they take a bytes parameter. This option has pros and cons so there is still some analysis to carry out in this regard, which includes exploring other options.

Looping in @NicolasMassart and @pinges since I discussed this issue with him a couple of months ago. It would be the follow-up of this other solved issue.

If you think it makes sense, I would like to be the assignee of the issue.

Thanks in advance!

Acceptance Criteria

• We are able to use the Flexible Privacy Group feature along with Tessera's EC encryptor