PGP, or Pretty Good Privacy, is a data encryption and decryption program that provides cryptographic privacy and authentication for data communication. It is widely used for securing emails and files, ensuring that only intended recipients can read the information. PGP uses a combination of symmetric-key cryptography and public-key cryptography to achieve this security. Developed by Phil Zimmermann in 1991, PGP has become a standard for email encryption. It allows users to create a pair of keys: a public key for encrypting messages and a private key for decrypting them. This dual-key system enhances security and trust in digital communications.