Aggelos Kiayias, Alexander Russell, Bernardo David, Roman Oliynykov
cited 197 times
(1) the network is synchronous in the sense that an upper bound can be determined during which any honest stakeholder is able to communicate with any other stakeholder
(2) a number of stakeholders drawn from the honest majority is available as needed to participate in each epoch
(3) the stakeholders do not remain offline for long periods of time
(4) semi-adaptive security (corruptions with delay)
Input endorsers (Sec 7.1): Reward mechanism for incentivizing the participants to the system which we prove to be an (approximate) Nash equilibrium. In this way, attacks like block withholding and selfish-mining are mitigated by our design
chain growth only holds if $ α(1-f)^Δ ≥ (1+ε)/2, for some f, ε between 0 and 1
f is the probability that a hypothetical party controlling all 100% of the stake would be elected leader for a particular slot
Honest majority of stake
we control the effective power of adaptive adversaries in this setting with a stochastic dominance argument that permits us to carry out the analysis of the underlying blockchain guarantees (e.g., common prefix) with a single distribution that provably dominates all distributions on characteristic strings generated by adaptive adversaries.
Adapt the mechanism of input endorsers from Ouroboros
Ideal randomness (!?) with VRF
Following the examples of Algorand and Snow White, we show that security can be guaranteed despite any adversarial bias resulting from grinding
Leaky resettable beacon implemented by RNG (hash of concat of VRF outputs)
It leaks to the adversary, up to$ τslots prior to the end of an epoch, the beacon value for the next epoch.
Resettability: biasibility (see 4.6)
The adversary can reset the value returned by the functionality as many as$ rtimes
However, in the incentive structure of Ouroboros, slot leaders and endorsers who could potentially join an attack would receive rewards in both the main and the adversarial chain, resulting in those stakeholders not achieving higher profits by joining the attack.