The huge success of eBay has proven the demand for customer-to-customer (C2C) electronic commerce. eBay is a centralized infrastructure with all its scalability problems (network bandwidth, server load, availability, etc.). In this paper we argue that C2C e-commerce is an application domain that maps naturally onto the emergent field of P2P systems simply by its underlying interaction model of customers, i.e., peers. This offers the opportunity to take P2P systems beyond mere file sharing systems into interesting new application domains. The long-term goal would be to design a fully functional decentralized system which resembles eBay without eBay’s dedicated, centralized infrastructure. Since security (authenticity, non-repudiation, trust, etc.) is key to any e-commerce infrastructure, our envisioned P2P e-commerce platform has to address this adequately. As the first step in this direction we present an approach for a completely decentralized P2P public key infrastructure (PKI)...