Paper 2018/1046
Constructing Infinite Families of Low Differential Uniformity $(n,m)$Functions with $m>n/2$
Claude Carlet, Xi Chen, and Longjiang Qu
Abstract
Little theoretical work has been done on $(n,m)$functions when $\frac {n}{2}<m<n$, even though these functions can be used in Feistel ciphers, and actually play an important role in several block ciphers. Nyberg has shown that the differential uniformity of such functions is bounded below by $2^{nm}+2$ if $n$ is odd or if $m>\frac {n}{2}$. In this paper, we first characterize the differential uniformity of those $(n,m)$functions of the form $F(x,z)=\phi(z)I(x)$, where $I(x)$ is the $(m,m)$Inverse function and $\phi(z)$ is an $(nm,m)$function. Using this characterization, we construct an infinite family of differentially $\Delta$uniform $(2m1,m)$functions with $m\geq 3$ achieving Nyberg's bound with equality, which also have high nonlinearity and not too low algebraic degree. We then discuss an infinite family of differentially $4$uniform $(m+1,m)$functions in this form, which leads to many differentially $4$uniform permutations. We also present a method to construct infinite families of $(m+k,m)$functions with low differential uniformity and construct an infinite family of $(2m2,m)$functions with $\Delta\leq2^{m1}2^{m6}+2$ for any $m\geq 8$. The constructed functions in this paper may provide more choices for the design of Feistel ciphers.
Metadata
 Available format(s)
 Category
 Secretkey cryptography
 Publication info
 Published elsewhere. Minor revision. Designs, Codes and Cryptography
 DOI
 10.1007/s1062301805537
 Keywords
 APN functionDifferential UniformityNyberg's boundSubstitution boxesSemibent function
 Contact author(s)
 1138470214 @ qq com
 History
 20181102: received
 Short URL
 https://ia.cr/2018/1046
 License

CC BY
BibTeX
@misc{cryptoeprint:2018/1046, author = {Claude Carlet and Xi Chen and Longjiang Qu}, title = {Constructing Infinite Families of Low Differential Uniformity $(n,m)$Functions with $m>n/2$}, howpublished = {Cryptology ePrint Archive, Paper 2018/1046}, year = {2018}, doi = {10.1007/s1062301805537}, note = {\url{https://eprint.iacr.org/2018/1046}}, url = {https://eprint.iacr.org/2018/1046} }