Development of an Integral Cryptanalysis Tool

• Applicant: Mykola Poluianenko, Ph.D.
• Subject Area: Security and Dependability, Operating-, Communication- and Distributed Systems
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 567006664

Cryptographic algorithms play a fundamental role in ensuring the confidentiality, integrity, and authenticity of data in information systems. Today, symmetric-key (block) ciphers are the cornerstone of most cryptographic primitives and, thanks to their performance advantages, play a decisive role in modern cryptography. The ability to assess their security is of great practical importance as well as theoretical interest. The security of block ciphers is always evaluated in terms of their resistance to specific attacks. Overall, the community has developed a fairly good understanding of block cipher security, and the security arguments have become considerably more precise. However, for some of the most fundamental properties that a block cipher must possess, robust arguments are still lacking. One such property is related to the class of attacks known as integral attacks. Integral cryptanalysis is an important method for attacking symmetric-key primitives. The term "integral cryptanalysis" refers to the computation of an "integral" over the primitive, which can be interpreted as summing ist outputs over a selected set of inputs. However, in general, the calculation of the integral resistance metric is a complex task that requires significant computational resources. This situation prevents a comprehensive evaluation of the resistance of many encryption schemes to integral attacks - let alone the development of a methodology for designing cryptographic primitives with a specified level of integral resistance within acceptable time and resource constraints. At present, reliable arguments are often limited to very specific cases, leaving a gap in the comprehensive security analysis of block ciphers. The development of a practical methodology for integral cryptanalysis will help address this issue. The primary objective of this project is to develop tools that reduce the computational complexity of determining the integral resistance of block ciphers and enable the practical computation of integral resistance for a wide range of cryptographic primitives. As a practical application of the results of this work, the following are planned: 1) The development of software for determining the integral resistance values of block ciphers based on SPN and Feistel constructions; 2) The development of software (hardware-software solutions) for generating S-boxes that are resistant to integral cryptanalysis (without compromising other cryptographic properties); 3) Conducting research into the vulnerability of some existing encryption algorithms to integral cryptanalysis.

• DFG Programme: Research Grants