48 research outputs found
Agent-Based Simulations of Blockchain protocols illustrated via Kadena's Chainweb
While many distributed consensus protocols provide robust liveness and
consistency guarantees under the presence of malicious actors, quantitative
estimates of how economic incentives affect security are few and far between.
In this paper, we describe a system for simulating how adversarial agents, both
economically rational and Byzantine, interact with a blockchain protocol. This
system provides statistical estimates for the economic difficulty of an attack
and how the presence of certain actors influences protocol-level statistics,
such as the expected time to regain liveness. This simulation system is
influenced by the design of algorithmic trading and reinforcement learning
systems that use explicit modeling of an agent's reward mechanism to evaluate
and optimize a fully autonomous agent. We implement and apply this simulation
framework to Kadena's Chainweb, a parallelized Proof-of-Work system, that
contains complexity in how miner incentive compliance affects security and
censorship resistance. We provide the first formal description of Chainweb that
is in the literature and use this formal description to motivate our simulation
design. Our simulation results include a phase transition in block height
growth rate as a function of shard connectivity and empirical evidence that
censorship in Chainweb is too costly for rational miners to engage in. We
conclude with an outlook on how simulation can guide and optimize protocol
development in a variety of contexts, including Proof-of-Stake parameter
optimization and peer-to-peer networking design.Comment: 10 pages, 7 figures, accepted to the IEEE S&B 2019 conferenc
How to Rationally Select Your Delegatee in PoS
This paper centers around a simple yet crucial question for everyday users:
How should one choose their delegated validators within proof-of-stake (PoS)
protocols, particularly in the context of Ethereum 2.0? This has been a
long-overlooked gap, as existing studies have primarily focused on
inter-committee (validator set) behaviors and activities, while neglecting the
dynamic formation of committees, especially for individual stakeholders seeking
reliable validators. Our study bridges this gap by diving into the delegation
process (normal users delegate their small-value tokens to delegatees who later
act as validators) before entering an actual consensus phase.
We propose a Bayesian model to quantify normal users' trust in delegatees,
which we further incorporate into a game-theoretical model to simulate users'
reactions against a set of critical factors identified through extensive
research (including 10+ staking service provider as well as 30+ PoS
blockchains). Our results reveal that users tend to choose their delegatees and
utilize their tokens by carefully weighing the delegation cost, the behaviors
of other users, and the reputation of delegatees, ultimately reaching a Nash
equilibrium. Unfortunately, the collective trend significantly increases the
likelihood of token concentration on a small number of delegatees
Liquid Proof-of-Stake in Tezos: An Economic Analysis
n this paper, we investigate some economic fundamentals related to the Tezos blockchain platform under the Emmy* consensus protocol. The protocol is based on a liquid version of Proof-of-Stake, in the sense that users can temporarily delegate some or all of their Tz units to full nodes. In addition to increasing the stake of the full node, and thus the probability of being selected as a block baker/endorser, such delegation induces the property of the super-additivity of users’ selection probability of baking/endorsing a block. That is, with delegation, the selection probability may be larger than the sum of the selection probabilities without delegation. In this paper, we study how monetary holdings and stakes can evolve with time, also discussing the individual user and the market implications of delegation