Which of the following are building blocks of PKI authentication?

The building blocks of Public Key Infrastructure (PKI) authentication include various components that work together to ensure secure communication and identity verification. Among the options provided, cryptographic algorithms play a crucial role in this framework. They are essential for establishing secure connections by enabling the processes of encryption and decryption, which protect data as it travels across networks.

Cryptographic algorithms underpin the operation of PKI by facilitating the creation of digital signatures and certificates. Digital signatures ensure that messages or documents can be verified as authentic and have not been tampered with, while digital certificates authenticate the identity of individuals or organizations. These algorithms must be robust and widely accepted to create trust among users in a PKI system.

The other options, while important in the realm of IT security, do not serve as foundational components specifically for PKI authentication. Firewall protocols are mainly focused on network security, encryption keys are essential but are dependent on cryptographic algorithms for their generation and usage, and database management systems, while necessary for data storage and retrieval, do not directly contribute to the authentication process in PKI.