Existing centralised market places such as Ebay enable companies to gather large amounts of personal data that can be used to manipulate users. Furthermore, users can frequently perform fraud without severe consequence. Reputation systems only solve this problem partially as malicious users can re-join the network with a new identity if their reputation is too low. By performing a Sybil attack, i.e., joining with multiple seemingly distinct identities, malicious participants can further boost their own reputation. In this paper, we present MarketPalace. MarketPalace relies on a peer-to-peer infrastructure to realize a decentralized market place during trading. Only when registering, users communicate with a central server to verify that they are not Sybils. More concretely, our system leverages self-sovereign identity to detect and undermine repeated joins by the same user. We implemented MarketPalace and demonstrated its feasibility for small regional markets.

翻译：Ebay等现有集中化市场场所使公司能够收集大量个人数据,用来操纵用户。此外,用户经常进行欺诈,而不会产生严重后果。光荣系统只能部分解决这个问题,因为恶意用户如果声誉太低,只能以新的身份重新加入网络。通过Sybil攻击,即与多个看似不同的身份结合,恶意参与者可以进一步提升自己的声誉。在本文中,我们展示了市场Palace。市场Palace依靠对等基础设施来实现交易过程中的分散化市场。只有在注册时,用户才与中央服务器通信,以核实他们不是Sybils。更具体地说,我们的系统利用自我主权身份来探测和破坏同一用户的重复加入。我们实施了市场Palace,并展示了它对于小型区域市场的可行性。