New Analysis of Reduced-Version of Piccolo in the Single-Key Scenario
Ya Liu, Liang Cheng, Fengyu Zhao, Chunhua Su, Zhiqiang Liu, Wei Li, Dawu Gu · KSII Transactions on Internet and Information Systems · 2019
The lightweight block cipher Piccolo adopts Generalized Feistel Network structure with 64 bits of block size.Its key supports 80 bits or 128 bits, expressed by Piccolo-80 or Piccolo-128, respectively.In this paper, we exploit the security of reduced version of Piccolo from the first round with the pre-whitening layer, which shows the vulnerability of original Piccolo.As a matter of fact, we first study some linear relations among the round subkeys and the properties of linear layer.Based on them, we evaluate the security of Piccolo-80/128 against the meet-in-the-middle attack.Finally, we attack 13 rounds of Piccolo-80 by applying a 5-round distinguisher, which requires 2 44 chosen plaintexts, 2 67.39 encryptions and 2 64.91 blocks, respectively.Moreover, we also attack 17 rounds of Piccolo-128 by using a 7-round distinguisher, which requires 2 44 chosen plaintexts, 2 126 encryptions and 2 125.49blocks, respectively.Compared with the previous cryptanalytic results, our results are the currently best ones if considering Piccolo from the first round with the pre-whitening layer.