Information security - Authenticated encryption

This document specifies five methods for authenticated encryption, i.e. defined ways of processing a data string with the following security objectives:

- data confidentiality, i.e. protection against unauthorized disclosure of data;

- data integrity, i.e. protection that enables the recipient of data to verify that it has not been modified;

- data origin authentication, i.e. protection that enables the recipient of data to verify the identity of the data originator.

All five methods specified in this document are based on a block cipher algorithm, and require the originator and the recipient of the protected data to share a secret key for this block cipher.

Key management is outside the scope of this document. Key management techniques are defined in ISO/IEC 11770 (all parts).

Four of the mechanisms in this document, namely mechanisms 3, 4, 5 (AAD variant only) and 6, allow data to be authenticated which is not encrypted. That is, these mechanisms allow a data string that is to be protected to be divided into two parts, D, the data string that is to be encrypted and integrity-protected, and A (the additional authenticated data) that is integrity-protected but not encrypted.