International Association
for Cryptologic Research

Authenticity and confidentiality are crucial for maintaining a secure information infrastructure. Confidentiality prevents unauthorized disclosure, while authenticity ensures origin of the data.. Authenticated encryption ensures both simultaneously by protecting data from access and verifying integrity. This paper presents a NeevAs cipher suite offering authenticated encryption with associated data (AEAD) and hashing, based on a sponge-based duplex construction. The scheme included concurrent absorption, a novel sponge method, where associated data is absorbed into the capacity part and plaintext into the rate part simultaneously. This reduces permutation calls typically required for associated data processing compared to existing sponge based designs. In the NeevAs cipher suite, the modified Neeva hash function generates the security tag, and the Ascon S-box provides efficiency and resistance against differential and boomerang attacks. The design targets lightweight cryptography, minimizing permutation calls to enhance efficiency and reduce resource consumption, making it well-suited for resource-constrained devices.