Public Key Infrastructure also is known as digital authentication infrastructure is a technological solution to ensure safety (authentication, integrity, confidentiality, and non-repudiation) in digital transactions for subject entities (users and devices) exchanging information in the digital world.

The basic idea is that the two parties exchanging information (by participating in the transaction) using a password (public key) need a trusted third party to authenticate the key pair belonging to a specific entity through means of digital certificates. After the authentication of the key pair, the subject uses the authenticated key pair to ensure safety for their digital transactions (authentication, integrity, confidentiality, and non-repudiation).

The goal of digital authentication infrastructure is to ensure safety for digital transactions such as e-commerce, internet banking, confidential email, and more.