Malicious Board when processing responses

[gakonst]

Looking at the following piece of code, it seems to me that the following attack is possible by the board:

1. Alice and Bob want to download responses
2. Board sends different responses to each, one where the status matrix is all 1s and one where it's not
3. The set_statuses call will modify the status matrix of each participant
4. (wlog) Alice goes to Phase 3, while Bob sees no error responses and outputs his result

celo-threshold-bls-rs/crates/dkg-core/src/primitives/states.rs

Line 467 in c89dd0f

self.set_statuses(responses);

WDYT @nikkolasg @kobigurk

[kobigurk]

Yes, we definitely want a good broadcast channel. The coordinator approach should only be a stepping stone on the way and a trade-off if needed.