Final answer:
Public key infrastructure (PKI) enables secure communication over a network using asymmetric cryptography and a pair of keys: a public key and a private key. It is used in various applications such as secure email, digital signatures, and secure web browsing.
Step-by-step explanation:
Public key infrastructure (PKI) refers to a set of technologies and processes that enable secure communication over a network. It involves the use of asymmetric cryptography which utilizes a pair of keys: a public key and a private key. The public key is used to encrypt data, while the private key is used to decrypt it. PKI is used in various applications such as secure email, digital signatures, and secure web browsing.
For example, consider secure online banking. When you access your bank's website, your computer requests the bank's digital certificate (which contains the bank's public key) to establish a secure connection. The bank's server uses its private key to decrypt the data sent by your computer, ensuring that it is authentic and secure.