Linear approximation attacks on reduced-round block ciphers
*Swapnil SonawaneCorresponding authorswapnil.Sonawane@vit.edu.inDepartment of Computer EngineeringWadalaVidyalankar Institute of TechnologyMumbai, Maharashtra, IndiaView full profile → , Dilip Motwanidilip.motwani@vit.edu.inDepartment of Information TechnologyVidyalankar Institute of TechnologyMumbai, Maharashtra, 400037, IndiaView full profile → , Vidya Chitrevidya.chitre@vit.edu.inDepartment of Information TechnologyVidyalankar Institute of TechnologyMumbai, Maharashtra, 400037, IndiaView full profile → , Amit Nerurkaramit.nerurkar@vit.edu.inDepartment of Computer EngineeringVidyalankar Institute of TechnologyMumbai, Maharashtra, IndiaView full profile → , Varsha Bhosalevarsha.bhosale@vit.edu.inDepartment of Information TechnologyVidyalankar Institute of TechnologyMumbai, Maharashtra, 400037, IndiaView full profile → , Rugved Deolekarrugved.deolekar@vit.edu.inDepartment of Information TechnologyVidyalankar Institute of TechnologyMumbai, Maharashtra, 400037, IndiaView full profile →
* Corresponding author · click or hover a name for details
- Received:
- 01 Apr 2026
- Published Online:
- 31 Oct 2026
- Article type:
- Research Article
- Language:
- EN
- Article no.:
- JDMSC-3037
- Pages:
- 4121–4131
Abstract
Linear cryptanalysis is still a key method to analyze the security of symmetric-key primitives, especially reduced-round block ciphers, in which structural weaknesses are more revealed. This paper examines linear approximation attacks on reduced-round variants of substitution permutation networks (SPNs) and Feistel ciphers, including finding high bias linear expressions in S-box layers and key mixing. The approach combines the linear hull analysis and the statistical hypothesis testing to accumulate the bias during several rounds, thus providing a way to recover keys. Experimental analysis shows that reduced-round designs have quantifiable biases up to 0.125, and achieve successful key recovery probabilities above 92.4 percent with much less plaintext-ciphertext pairs than designs using full rounds.
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References
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