Public Key Cryptography is a method of encrypting data that uses a pair of keys: a public key, which can be shared with anyone, and a private key, which is kept secret. This system allows secure communication over the internet, as messages encrypted with the public key can only be decrypted by the corresponding private key. This technology underpins many online security protocols, including SSL/TLS for secure web browsing and PGP for email encryption. By ensuring that only the intended recipient can read the message, Public Key Cryptography plays a crucial role in maintaining privacy and security in digital communications.