Module agora.consensus.EnrollmentManager

This class currently has 3 responsibilities: - It's a bridge to the ValidatorSet, where the list of currently active validators is stored; - It stores Enrollments that are not yet part of the validator set; - Most importantly, if this node is a validator, it manages this node's Enrollment data, including pre-images.

The consensus protocol requires each validator to commit to a hash and to reveal a pre-image for the next ValidatorCycle blocks (currently 1008). That newly-revealed hash is used as a basis for various operations, such as deriving the new signature noise (in order to make signature aggregation possible) and both as a source of randomness for the node itself (e.g. for the quorum balancing) and as part of the network randomness function, when aggregated with other node's pre-images. As a result, revealing the pre-image in time is absolutely critical and not doing so will lead to penalties.

In order to ensure that we will never lose the ability to reveal pre-images, this implementation uses a reproducible scheme: on the first run, we generate a "cycle seed" which is derived from a hash of the private key, a constant string, and a constant value (0). Using this cycle seed, we generate a large amount of pre-images (currently 5_040_000). Then out of this range of [0 .. 5_040_000] pre-images, we reveal the last 1008 (ValidatorCycle), or in D terms [$ - 1008 .. $]. When the first enrollment runs out, we reveal the next last 1008, or in D terms [$ - 2016 .. $ - 1008]. When the cycle is expired, we re-generate a new cycle seed. By using this scheme, a node that would start from scratch with an already-enrolled key will be able to recover its cycle index by scanning the blockchain, and resume validating.

Classes