Improved Automatic Search Tool for Bit-Oriented Block Ciphers and Its Applications
Abstract
The tool based on Mixed-integer Linear Programming (MILP) is simple and effective that frequently used in searching some different types of distinguishers recently. In this paper, we mainly focus on the automatic search method using MILP and the optimizer Gurobi for bit-oriented block ciphers.
We introduce the OPB file format to construct MILP models for the bit-oriented block ciphers. Compared to the LP file format, it is more concise and suitable to deal with boolean variables. And we modify the high-level strategy to reduce the solution time by setting parameter MIPFocus provided by the optimizer Gurobi. Moreover, the new simple linear inequalities of differential pattern propagation of modular addition are given without considering the differential probability in the impossible differential search. As applications, we give the exact lower bounds of the number of differential active s-boxes for 5\(\sim \)12 rounds LBlock in the related-key model and all of impossible differentials limited the input and output differences to only 1 active bit for the full versions of SPECK.
Keywords
Related-key differentials Impossible differentials LBlock SPECK MILPNotes
Acknowledgments
The authors would like to thank all anonymous referees for their valuable comments that greatly improve the manuscript. This work is supported by National Natural Science Foundation of China (No. 61672509, No. 61232009) and National Cryptography Development Fund (MMJJ20170101).
References
- 1.Mouha, N., Wang, Q., Gu, D., Preneel, B.: Differential and linear cryptanalysis using mixed-integer linear programming. In: Wu, C.-K., Yung, M., Lin, D. (eds.) Inscrypt 2011. LNCS, vol. 7537, pp. 57–76. Springer, Heidelberg (2012). https://doi.org/10.1007/978-3-642-34704-7_5CrossRefMATHGoogle Scholar
- 2.Sun, S., Hu, L., Wang, P., Qiao, K., Ma, X., Song, L.: Automatic security evaluation and (related-key) differential characteristic search: application to SIMON, PRESENT, LBlock, DES(L) and other bit-oriented block ciphers. In: Sarkar, P., Iwata, T. (eds.) ASIACRYPT 2014, Part I. LNCS, vol. 8873, pp. 158–178. Springer, Heidelberg (2014). https://doi.org/10.1007/978-3-662-45611-8_9CrossRefGoogle Scholar
- 3.Stein, W., et al.: Sage: Open source mathematical software (2008)Google Scholar
- 4.Xiang, Z., Zhang, W., Bao, Z., Lin, D.: Applying MILP method to searching integral distinguishers based on division property for 6 lightweight block ciphers. In: Cheon, J.H., Takagi, T. (eds.) ASIACRYPT 2016, Part I. LNCS, vol. 10031, pp. 648–678. Springer, Heidelberg (2016). https://doi.org/10.1007/978-3-662-53887-6_24CrossRefGoogle Scholar
- 5.Sasaki, Y., Todo, Y.: New Impossible differential search tool from design and cryptanalysis aspects. In: Coron, J.-S., Nielsen, J.B. (eds.) EUROCRYPT 2017, Part III. LNCS, vol. 10212, pp. 185–215. Springer, Cham (2017). https://doi.org/10.1007/978-3-319-56617-7_7CrossRefGoogle Scholar
- 6.Gurobi Optimization: Gurobi optimizer reference manual (2013). http://www.gurobi.com
- 7.Fu, K., Wang, M., Guo, Y., Sun, S., Hu, L.: MILP-based automatic search algorithms for differential and linear trails for speck. In: Peyrin, T. (ed.) FSE 2016. LNCS, vol. 9783, pp. 268–288. Springer, Heidelberg (2016). https://doi.org/10.1007/978-3-662-52993-5_14CrossRefGoogle Scholar
- 8.Cui, T., Jia, K., Fu, K., et al.: New Automatic Search Tool for Impossible Differentials and Zero-Correlation Linear Approximations. Cryptology ePrint archive, Report 2016/689 (2016). https://eprint.iacr.org/2016/689
- 9.Lee, H.C., Kang, H.C., Hong, D., et al.: New Impossible Differential Characteristic of SPECK64 using MILP. Cryptology ePrint archive, Report 2016/1137 (2016). https://eprint.iacr.org/2016/1137
- 10.Wu, W., Zhang, L.: LBlock: a lightweight block cipher. In: Lopez, J., Tsudik, G. (eds.) ACNS 2011. LNCS, vol. 6715, pp. 327–344. Springer, Heidelberg (2011). https://doi.org/10.1007/978-3-642-21554-4_19CrossRefGoogle Scholar
- 11.Sun, S., Hu, L., Wang, M., et al.: Towards finding the best characteristics of some bit-oriented block ciphers and automatic enumeration of (related-key) differential and linear characteristics with predefined properties. Cryptology ePrint Archive, Report 2014/747 (2014). https://eprint.iacr.org/2014/747
- 12.Beaulieu, R., Shors, D., Smith, J., Treatman-Clark, S., Weeks, B., Wingers, L.: The SIMON and SPECK famillies of lightweight block ciphers. Cryptology ePrint archive, Report 2013/543 (2013). http://eprint.iacr.org/2013/543