This adds a bit of special handling to make sure messages don't stay in
the queue forever in the `dynamic_honey_badger` tests, even if there is
only one validator: the problem was that the single validator is always
ready for input, so it never processed incoming messages. However, to
add the new validator, it needs to process the joining node's key
generation messages.
`DynamicHoneyBadger` now also removes committed key generation messages
from the queue, to avoid committing duplicates.
Random adversaries are created for `broadcast` and `honey_badger`. Random value generation was added for all type-dependencies of these algorithms, causing the `Rand` trait to be implement for a large portion of the codebase.
Additionally, `MessageWithSender` turned into an actual struct, making it much easier to handle. Tuple-like construction is still available through `MessageWithSender::new()`.
* Clear outdated key gen messages from the buffer.
* Process output after proposing, to make `HoneyBadger` work with a
single validator.
* Print an error if threshold decryption fails.
* Verify decryption shares with the correct ciphertext.
* Insert all ciphertexts from an epoch at once; otherwise contributions
can be omitted from a batch.
* Remove `BoolWithFaultLog`: It's easier to return a tuple, and it's
used only in one place now.
* Avoid redundant signature verification in `VoteCounter`.
* Fix the tests for `QueueingHoneyBadger`.
* Use fewer network sizes to speed up tests a bit.
This makes Honey Badger a bit more complicated but a lot more flexible:
It is now unaware of transactions and basically just runs one Subset
instance per epoch.
That way, users can use any kind of external queue, control throttling
and prioritization.
This allows the caller to address nodes by ID instead of by index.
Also contains a few other minor changes that will be needed for
`DynamicHoneyBadger`.
This is a _synchronous_ key generation algorithm. We will use it in
`DynamicHoneyBadger`, on top of `HoneyBadger` to satisfy the synchrony
requirements.
It can also be used independently e.g. on top of a blockchain.