Public Key Infrastructure (PKI) is the set of hardware, software, policies, processes, and procedures required to create, manage, distribute, use, store, and revoke digital certificates and public-keys. PKIs deliver elements essential for a secure and trusted business environment for e-commerce and the growing Internet of Things (IoT) PKIs help establish the identity of people, devices, and services enabling controlled access to systems and resources, protection of data, and accountability in transactions.”]
Source: https://cpl.thalesgroup.com/faq/public-key-infrastructure-pki/what-public-key-infrastructure-pki