End-to-end encryption is a term used to describe a communication system where the only the sender (the origin end) and the recipient (the destination end) of a message, and no intermediaries, can read the subject message, which is rigorously encrypted throughout its transit from the source end to the receiver end. When end-to-end encryption is properly implemented, only the sender and the recipient of the message possess the cryptographic keys needed to decrypt the message—even the intermediate message service has
zero knowledge of the cryptographic keys required.