FlexAEAD v1.1 -A Lightweight AEAD Cipher with Integrated Authentication

Abstract

This paperdescribes a symmetrical block cipher family – FlexAEAD v1.1. This is an updated version of the work presented as round 1 candidate on the contest for NIST lightweight crypto standardization process. It was engineered to be lightweight, consuming less computational resources than other ciphers and to work with different block and key sizes. Other important characteristic is to integrate the authentication on its basic algorithm. This approach is helps to reduce the resource needs. The algorithm capacity to resist against linear and different cryptanalysis attacks was evaluated. The FlexAEAD also supports the authentication of the Associated Data (AD). The version 1.1 makes the algorithm resistant to iterated differential attacks. It also resolves a padding attack on the AD that allowed messages to have the same tag if the last AD block was filled with zeros.