The lightweight cryptosystem TinyJambu: security and applications in IoT environments

Abstract TinyJambu is one of the 10 finalists in the NIST Lightweight Cryptography Standardization Project. This Authenticated Encryption with Associated Data algorithm is very fast and extremely small in terms of hardware implementation. In this work, we study a differential cryptanalytic attack against TinyJambu. It is a deeper analysis than previous works found in the literature as well as it also obtains better differential probabilities than those of other studies. More precisely, we develop a differential forgery attack with probability 2–65.7845, what is much better than 2−80 obtained by the own designers and better than 2–70.12 the best probability obtained by other authors. In brief, we have reduced the margin of security against a forgery attack for this proposal of lightweight cryptosystem. Later, NIST allows to tweak TinyJambu by increasing the number of rounds from 384 up to 640. This round increment means a greater security margin than before. For this updated version of TinyJambu, we analyse some properties of the new algorithm that allow TinyJambu to be considered for particular IoT applications as well.