IdAPoS is an identity-based consensus protocol for decentralised Blockchain networks that implements a trustless reputation system by extending Proof-of-Stake to facilitate leader selection in non-economic contexts. Like any protocol operating in a public/permissionless setting, it is vulnerable to Sybil attacks in which byzantine actors interfere with peer sampling by presenting artificially large numbers of identities. This paper demonstrates what influence these attacks have on the stability of member selection of a Blockchain system using the IdAPoS protocol and investigates how attacks can be mitigated. As a novel protocol, its vulnerability to this type of attack has not previously been researched. The research question is approached via an agent-based model of an IdAPoS system in which both honest and malicious actors are represented as agents. Simulations are run on some reasonable configurations of an IdAPoS system that employ different attack mitigation strategies. The results show that a super strategy that combines multiple individual mitigation strategies is more effective for containing Sybil attacks than the unmitigated protocol and any other individual strategies proposed. In the simulation this strategy extended the time until a system was taken over by a malicious entity approximately by a factor of 5. These positive initial results indicate that further research into the practical viability of the protocol is warranted.

IdAPoS 是一种用于去中心化区块链网络的基于身份的共识协议，它通过扩展权益证明来促进非经济环境中的领导者选择，从而实现去信任的声誉系统。与在公共/无许可环境中运行的任何协议一样，它容易受到 Sybil 攻击，在这种攻击中，拜占庭行为者通过人为呈现大量身份来干扰对等采样。本文展示了这些攻击对使用IdAPoS协议的区块链系统成员选择的稳定性有何影响，并研究了如何减轻攻击。作为一种新颖的协议，它对此类攻击的脆弱性以前没有被研究过。研究问题是通过IdAPoS的基于代理的模型来解决的诚实和恶意行为者都被表示为代理的系统。在采用不同攻击缓解策略的IdAPoS系统的一些合理配置上运行模拟。结果表明，结合多个单独缓解策略的超级策略比未缓解协议和提出的任何其他单独策略更有效地遏制女巫攻击。在模拟中，这种策略将系统被恶意实体接管的时间延长了大约 5 倍。这些积极的初步结果表明，有必要进一步研究该协议的实际可行性。