Authenticated Encryption

cryptography

Definition

Authenticated Encryption

Authenticated encryption is encryption that provides both confidentiality and integrity protection.

Meaning

An authenticated encryption scheme does not merely hide the plaintext. It also lets the receiver detect whether the ciphertext was modified.

This prevents attacks in which encrypted fields are copied, rearranged, or changed in place.

Confidentiality without integrity is not enough

A ciphertext may conceal the plaintext and still be unsafe if an attacker can modify it so that the decrypted message changes from logs to flag or from visitor to curator.

Constructions

Authenticated encryption can be achieved by using an authenticated mode such as GCM, or by combining encryption with a separate integrity mechanism such as HMAC in a sound construction.