3.1 Denial of Service by Malicious Initiator

[pavelkrolevets]

Problem:
In InitInstance, any INIT message with a valid signature causes an entry to be added to the s.Instances array. If that array contains 1024 entries not older than 5 minutes, no new DKG can be initiated. Due to Signature verification allows arbitrary public key, anyone with network access can create valid INIT messages, easily denying service to the legitimate initiator.

Solution:

1. increase instances to max 1024 * 100. This will increase hardware requirements but to not critical point as its quite low now.
2. decrease rate limit to init/resign/reshare routes to 100.
3. decrease time to live for instances to 1 minute, as this is more than enough to finish all phases of DKG ceremonies.

In this case, to ddos an attacker needs >= 1024 different IP addresses.

[pavelkrolevets]

integration tests are failing because of request limits reach. We need to update tests to run not more than 100 requests in a minute.