This chapter demonstrates the nature of information asymmetry in the public key infrastructure (PKI) market by using the lemons principle. PKI has been developed as a key security technology to provide trust in online transactions and communications. Trust in e-commerce is understood in terms of security principles such as authentication, confidentiality, authorization, and nonrepudiation. PKI is developed with the intention of realizing these security principles in an electronic environment. In the PKI model, certification authority (CA) bears the greatest responsibility for establishing trust in the electronic world between two mutually unfamiliar identities. In the PKI market, people detect the adoption of branding as a marketing strategy for attracting potential certificate subscribers. Akerlof's theory is used to explain the problem of quality uncertainty resulting from asymmetry of information between buyers and sellers in markets. Many researchers have suggested one possible solution through the concept of signaling in which the market problems of quality uncertainty and information asymmetry may be reduced.