End-to-end encryption (E2EE)
It is a method used for securing encrypted data while it is moving from source to the destination. In End-to-End Encryption, the data is encrypted on the sender's system and only the intended recipient will be able to decrypt it. Nobody in between (be they an internet service provider, application service provider or hacker, ...) can read it or tamper with it, thereby providing a great deal of confidentiality and protection to all of your communications.
Digital signatures
It is an equivalent of a handwritten signature or stamped seal, but offering far more inherent security. A digital signature is intended to solve the problem of tampering and impersonation in digital communications. It gives absolute authenticity and integrity to all of your messages.