PKI (Public Key Infrastructure) is a comprehensive framework used to manage digital certificates and public-key encryption. It enables secure electronic transfer of information for various network activities, such as internet banking, email, and e-commerce. PKI uses a pair of cryptographic keys - public and private - to authenticate users, encrypt data, and ensure data integrity. The infrastructure includes certificate authorities (CAs), registration authorities (RAs), and other components that issue, validate, and revoke digital certificates. By establishing a trusted environment, PKI helps prevent unauthorized access, data breaches, and impersonation attacks. It is essential for implementing secure communications and digital signatures in modern IT systems.