# ECIES with AES-GCM

The Elliptic Curve Integrated Encryption Scheme (ECIES) describes how to derive a "temporal" key, encrypt a message (eg. using AES) and creating a MAC.

However, from my understanding using AES in GCM mode makes using an additional MAC obsolete. So, is it then safe to skip the MAC calculation step in ECIES when using AES-GCM?

• The AAD information you give GCM can either be empty, or optionally include a shared secret ($S_2$ on the Wikipedia article)