What is public key infrastructure (PKI) primarily used for?

Public Key Infrastructure (PKI) is primarily used for managing digital certificates, which are critical components in securing communications and validating the identity of entities over the internet. A digital certificate serves as an electronic "passport" that confirms the ownership of a public key by the named subject of the certificate. This process ensures that when data is sent over the internet, the sender can be authenticated, and the data can be encrypted for secure transmission.

PKI provides the necessary framework to issue, manage, and revoke digital certificates, enabling secure e-commerce, secure email, and other secure communications. It employs trusted third parties called Certificate Authorities (CAs) to validate the identity of individuals and organizations, thereby fostering trust in electronic transactions.

While options like storing encryption keys or distributing software updates are important in their own contexts, they do not encapsulate the core function of PKI the way managing digital certificates does. Moreover, creating backup copies of data is entirely different from the security and identity management that PKI provides. Thus, managing digital certificates stands out as the primary purpose of PKI, which forms the basis for secure communication in a variety of digital interactions.