Public Key Infrastructures (PKI) secure digital communications by providing a framework for managing digital certificates and encryption keys. This system enables secure transmissions over insecure networks by using pairs of cryptographic keys—public and private. The public key encrypts data, while the corresponding private key decrypts it, ensuring that only authorized parties can access the information. Additionally, PKI facilitates user authentication and data integrity, establishing trust among users. By employing PKI, organizations can protect sensitive information and maintain the confidentiality of their communications, which is essential for secure transactions in the digital world.