Fruit swMATH ID: 40835 Software Authors: Vahid Amin Ghafari, Honggang Hu, Ying Chen Description: Fruit-v2: Ultra-Lightweight Stream Cipher with Shorter Internal State. A few lightweight stream ciphers were introduced for hardware applications in the eSTREAM project. In FSE 2015, while presenting a new idea (i.e. the design of stream ciphers with the shorter internal state by using a secret key, not only in the initialization but also in the keystream generation), Sprout was proposed. Unfortunately, Sprout is insecure. Because Grain-v1 is the lightest cipher in the portfolio of the eSTREAM project, we introduce Fruit-v2 as a successor of the Grain-v1 and Sprout. It is demonstrated that Fruit-v2 is safe and ultra-lightweight. The size of LFSR and NFSR in Fruit-v2 is only 80 bits (for 80-bit security level), while for resistance to the classical time-memory-data trade-off attack, the internal state size should be at least twice of the security level. To satisfy this rule and to design a concrete cipher, we used some new design ideas. The discussions are presented that Fruit-v2 can be more resistant than Grain-v1 to some attacks such as classical time-memory-data trade-off. The main objective of this work is to show how it is possible to exploit a secret key in a design to achieve smaller area size. It is possible to redesign many of stream ciphers (by the new idea) and achieve significantly smaller area size by the new idea. Homepage: https://eprint.iacr.org/2016/355 Related Software: Trivium; Grain; eSTREAM; MICKEY; KATAN; KTANTAN; PRESENT; Enocoro; FAN; eBACS; LED; TWINE; KLEIN; LBlock; Fish; LEX Cited in: 7 Publications all top 5 Cited by 21 Authors 2 Hamann, Matthias 2 Krause, Matthias 2 Meier, Willi 2 Qi, Wenfeng 2 Zhao, Xiaoxin 1 Dey, Sabyasachi 1 Du, Shaoyu 1 Feng, Dengguo 1 Gong, Xinxin 1 Hao, Yonglin 1 Hell, Martin 1 Jiao, Lin 1 Johansson, Thomas 1 Maksimov, Alexander I. 1 Roy, Tapabrata 1 Sarkar, Santanu 1 Wang, Zhongxiao 1 Yoshida, Hirotaka 1 Zhang, Bin 1 Zhang, Jiamin 1 Zheng, Qunxiong Cited in 2 Serials 3 Designs, Codes and Cryptography 2 Cryptography and Communications Cited in 3 Fields 7 Information and communication theory, circuits (94-XX) 2 Number theory (11-XX) 1 Computer science (68-XX) Citations by Year