The internet of things (IoT) is described as the arrangement of physical articles—contraptions, automobiles, structures, and various things—fixed with equipment, programming, devices, and framework accessibility that engages these things to accumulate and exchange data. Practically paying little mind to industry, IoT is anticipated to be the absolute most significant factor affecting basic business rationale in the coming decades. PKI is the best alternative for arrangement suppliers to secure information and associated gadgets. When effectively executed, PKI can fabricate and bolster security and trust in IoT biological systems. PKI's job in IoT gives solid personality validation and makes the establishment of trust that frameworks, gadgets, applications, and clients need to securely connect and trade delicate information. PKI and the brought forth trust networks spread the basic security necessities IoT tasks need, giving the encryption, confirmation, and information respectability that make the establishment of trust. This chapter explores PKI-based security architecture.