Ascon (cipher)

Ascon is a family of lightweight authenticated ciphers and hash functions designed for devices with very little memory, power or processing capacity. It was developed in 2014 by researchers from Graz University of Technology, Infineon Technologies, Lamarr Security Research and Radboud University, became a finalist of the CAESAR competition in 2019, and was chosen by the US National Institute of Standards and Technology in 2023 for lightweight cryptography. NIST published the standard as Special Publication 800-232 in August 2025. The design is a sponge construction over a 320-bit state, with a substitution layer based on a modified Keccak S-box and a linear diffusion layer, so the same core can serve as an encryption scheme, a hash, an extendable-output function or a message authentication code. Variants such as Ascon-128, Ascon-128a, Ascon-Hash and Ascon-Xof share the permutation but differ in key length, rate and number of rounds.