Pretty Good Privacy (PGP)

Ordinary email was never designed to behave like a sealed envelope. A message can pass through multiple systems before it reaches the recipient, and without added protection it may be exposed to administrators, attackers, or anyone who can observe the traffic or storage along the way. For people handling sensitive information, that weakness is a serious problem.

PGP was created to solve that problem by giving users a way to protect both secrecy and trust. A message can be encrypted so that only the intended recipient can read it, and it can also be signed so the recipient can check who sent it and whether it changed in transit. That combination made PGP one of the most influential ideas in secure communication.

PGP is a hybrid cryptographic system that protects messages and files by combining public key cryptography, symmetric encryption, and digital signatures. Its strength comes from handling several needs at once: keeping content secret, proving who sent it, and showing whether it was altered. The system works well when the surrounding trust practices are strong, especially key verification and private key protection.