Explanation

Public Key Infrastructure (PKI) is a comprehensive framework governing digital security infrastructure and cybersecurity:

– It manages asymmetric cryptography through the creation, distribution, storage, and revocation of digital certificates and public-private key pairs.
– A trusted third-party known as a Certifying Authority (CA) (licensed in India under the Information Technology Act, 2000 by the Controller of Certifying Authorities) digitally signs certificates to verify the authentic identity of individuals, web servers, and digital devices.
– PKI secures digital signatures, encrypted emails, online banking, and e-governance portals.

Therefore, the term is used in the context of Digital security infrastructure — Option A.