Symmetric Ciphers For Emerging Applications

• Applicant: Professor Dr. Gregor Leander
• Subject Area: Security and Dependability, Operating-, Communication- and Distributed Systems
• Term: from 2017 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 326921743

• Final Report Year: 2020

Final Report Abstract

In this project we successfully investigated ciphers for emerging applications. As planned, our results were two-fold. On the one hand, we derived new cryptanalytic results on such ciphers. In particular we provided the best-known attacks on the block cipher PRIDE and the message authentication scheme MergeMAC. We also provided new design guidelines for key-schedules. In order to resist invariant attacks, that have recently broken a number of lightweight ciphers, we were able to provide clear and easy to compute criteria the round constants have to fulfil. On the other hand, given our new attacks and new design guidelines, we created several new designs. The ciphers RASTA and DASTA are the first constructions that optimize both for a small AND-depth and also for a small total number of ANDs per bit. The design MOE is our new design for another, and actually initially not even considered, emerging application scenario, i.e. protection against hardware trojans. Technically, this design required an in-depth study of the cryptographic criteria of modular multiplication (by a constant) which might be of independent interest.

Publications

• Differential Cryptanalysis of 18-Round PRIDE. INDOCRYPT 2017
  Virginie Lallemand, Shahram Rasoolzadeh
  (See online at https://doi.org/10.1007/978-3-319-71667-1_7)
• Proving Resistance Against Invariant Attacks: How to Choose the Round Constants. CRYPTO 2017
  Christof Beierle, Anne Canteaut, Gregor Leander, Yann Rotella
  (See online at https://doi.org/10.1007/978-3-319-63715-0_22)
• Rasta: A Cipher with Low ANDdepth and Few ANDs per Bit. CRYPTO 2018
  Christoph Dobraunig, Maria Eichlseder, Lorenzo Grassi, Virginie Lallemand, Gregor Leander, Eik List, Florian Mendel, Christian Rechberger
  (See online at https://doi.org/10.1007/978-3-319-96884-1_22)
• Universal Forgery and Multiple Forgeries of MergeMAC and Generalized Constructions. CT-RSA 2019
  Tetsu Iwata, Virginie Lallemand, Gregor Leander, Yu Sasaki
  (See online at https://doi.org/10.1007/978-3-030-12612-4_15)
• Dasta, Alternative Linear Layer for Rasta. IACR Trans. Symmetric Cryptol. 2020
  Phil Hebborn, Gregor Leander
  (See online at https://doi.org/10.13154/tosc.v2020.i3.46-86)