AEZ uses a non-standard AES variant in a sui generis fashion; as a result some people have called its security into question: https://eprint.iacr.org/2016/832.p

AEZ uses a non-standard AES variant in a sui generis fashion; as a result some people have called its security into question: https://eprint.iacr.org/2016/832.pdf https://eprint.iacr.org/2016/832.pdf Point being, its inclusion in the final CAESAR portfolio is far from clear at this point.