Public Key Infrastructure (PKI) is a framework used to manage digital keys and certificates, enabling security in online transactions. It ensures the authenticity and confidentiality of communications by pairing public and private keys.In this system, each user has a public key, which can be shared openly, and a private key, which is kept secret. The public key can encrypt data, while the private key is used to decrypt it. This structure allows users to verify identities and establish secure channels for transaction processes.PKI also relies on Certificate Authorities (CAs) that issue digital certificates, which confirm the legitimacy of public keys. These certificates are critical for establishing trust between parties. When a user receives a public key, they can check its certificate to confirm that it belongs to the correct owner.In summary, PKI enhances security and trust in transactions by managing keys and certificates, ensuring that users can engage safely and confidently in digital exchanges.