The SACI Special-Purpose Block Cipher
Paulo S. L. M. Barreto, Gustavo Yamasaki Martins Vieira, Wilson Vicente Ruggiero · 2007
SACI is a special-purpose iterated block cipher, targeted at certain applications with heavily constrained resources and very low traffic of encrypted messages. A typical scenario is the synchronization of tokens, an infrequent operation involving the exchange of just a few encrypted bytes under a fixed or seldom updated key. SACI is an instance of the Wide Trail family of algorithms which includes the AES cipher, and displays both involutional structure, in the sense that the encryption and decryption modes differ only in the key schedule, and cyclic key schedule, whereby the round subkeys can be computed in-place in any order.