{"title":"The complete weight enumerator of the square of one-weight irreducible cyclic codes","authors":"Canze Zhu","doi":"10.1007/s10623-025-01620-0","DOIUrl":"https://doi.org/10.1007/s10623-025-01620-0","url":null,"abstract":"<p>In this paper, for an odd prime power <i>q</i> and an integer <span>(mge 2)</span>, let <span>(mathcal {C}(q,m))</span> be a one-weight irreducible cyclic code with parameters <span>([q^m-1,m,(q-1)q^{m-1}])</span>, we consider the complete weight enumerator and the weight distribution of the square <span>(big (mathcal {C}(q,m)big )^2)</span>, whose dual has <span>(lfloor frac{m}{2}rfloor +1)</span> zeros. Using the character sums method and the known result of counting <span>(mtimes m)</span> symmetric matrices over <span>(mathbb {F}_q)</span> with given rank, we explicitly determine the complete weight enumerator of <span>(left( mathcal {C}(q,m)right) ^2)</span> and show that <span>(left( mathcal {C}(q,m)right) ^2)</span> is a <span>((2lfloor frac{m}{2}rfloor +1))</span>-weight cyclic code with parameters <span>([q^{m}-1,frac{m(m+1)}{2},(q-1)(q^{m-1}-q^{m-2})])</span>. Moreover, we get the weight distribution of the square of the simplex code by puncturing the last <span>(frac{(q-2)(q^m-1)}{q-1})</span> coordinates of <span>(left( mathcal {C}(q,m)right) ^2)</span>.</p>","PeriodicalId":11130,"journal":{"name":"Designs, Codes and Cryptography","volume":"56 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143672621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Limitations of the decoding-to-LPN reduction via code smoothing","authors":"Madhura Pathegama, Alexander Barg","doi":"10.1007/s10623-025-01617-9","DOIUrl":"https://doi.org/10.1007/s10623-025-01617-9","url":null,"abstract":"<p>The learning parity with noise (LPN) problem underlines several classic cryptographic primitives. Researchers have attempted to show the algorithmic difficulty of this problem by finding a reduction from the decoding problem of linear codes, for which several hardness results exist. Earlier studies used code smoothing as a technical tool to achieve such reductions for codes with vanishing rate. This has left open the question of attaining a reduction with positive-rate codes. Addressing this case, we characterize the efficiency of the reduction in terms of the parameters of the decoding and LPN problems. As a conclusion, we isolate the parameter regimes for which a meaningful reduction is possible and the regimes for which its existence is unlikely.\u0000</p>","PeriodicalId":11130,"journal":{"name":"Designs, Codes and Cryptography","volume":"20 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143672619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Binary stretch embedding of weighted graphs","authors":"Javad Ebrahimi Boroojeni, Mehri Oghbaei Bonab","doi":"10.1007/s10623-025-01608-w","DOIUrl":"https://doi.org/10.1007/s10623-025-01608-w","url":null,"abstract":"<p>In this paper, we introduce and study the problem of <i>binary stretch embedding</i> of edge-weighted graphs in both integer and fractional settings. Roughly speaking, the binary stretch embedding problem for a weighted graph <i>G</i> is to find a mapping from the vertex set of <i>G</i>, to the vertices of a hypercube graph such that the distance between every pair of the vertices is not reduced under the mapping, hence the name binary stretch embedding. The minimum dimension of a hypercube for which such a stretch embedding exists is called the binary addressing number of <i>G</i>. We show that the binary addressing number of weighted graphs is the optimum value of an integer program. The optimum value for the corresponding linear relaxation problem is called the fractional binary addressing number of <i>G</i>. This embedding type problem is closely related to the well-known <i>addressing problem</i> of Graham and Pollak and <i>isometric hypercube embedding problem</i> of Firsov. Using tools and techniques such as Hadamard codes and the linear programming theory help us to find upper and lower bounds, approximations, or exact values of the binary addressing number and the fractional variant of graphs. As an application of our results, we derive improved upper bounds or exact values of the maximum size of Lee metric codes of certain parameters.</p>","PeriodicalId":11130,"journal":{"name":"Designs, Codes and Cryptography","volume":"41 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143666542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Additive combinatorial designs","authors":"Marco Buratti, Francesca Merola, Anamari Nakić","doi":"10.1007/s10623-025-01594-z","DOIUrl":"https://doi.org/10.1007/s10623-025-01594-z","url":null,"abstract":"<p>A <span>(2-(v, k, lambda ))</span> design is additive if, up to isomorphism, the point set is a subset of an abelian group <i>G</i> and every block is zero-sum. This definition was introduced in Caggegi et al. (J Algebr Comb 45:271-294, 2017) and was the starting point of an interesting new theory. Although many additive designs have been constructed and known designs have been shown to be additive, these structures seem quite hard to construct in general, particularly when we look for additive Steiner 2-designs. One might generalize additive Steiner 2-designs in a natural way to graph decompositions as follows: given a simple graph <span>(Gamma )</span>, an <i>additive </i><span>((K_v,Gamma ))</span><i>-design</i> is a decomposition of the graph <span>(K_v)</span> into subgraphs (<i>blocks</i>) <span>(B_1,dots ,B_t)</span> all isomorphic to <span>(Gamma )</span>, such that the vertex set <span>(V(K_v))</span> is a subset of an abelian group <i>G</i>, and the sets <span>(V(B_1), dots , V(B_t))</span> are zero-sum in <i>G</i>. In this work we begin the study of additive <span>((K_v,Gamma ))</span>-designs: we develop different tools instrumental in constructing these structures, and apply them to obtain some infinite classes of designs and many sporadic examples. We will consider decompositions into various graphs <span>(Gamma )</span>, for instance cycles, paths, and <i>k</i>-matchings. Similar ideas will also allow us to present here a sporadic additive 2-(124, 4, 1) design.</p>","PeriodicalId":11130,"journal":{"name":"Designs, Codes and Cryptography","volume":"34 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143661406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"An attack on p-adic lattice public-key encryption cryptosystems and signature schemes","authors":"Chi Zhang","doi":"10.1007/s10623-025-01618-8","DOIUrl":"https://doi.org/10.1007/s10623-025-01618-8","url":null,"abstract":"<p>Lattices have many significant applications in cryptography. In 2021, the <i>p</i>-adic signature scheme and public-key encryption cryptosystem were introduced. They are based on the Longest Vector Problem (LVP) and the Closest Vector Problem (CVP) in <i>p</i>-adic lattices. These problems are considered to be challenging and there are no known deterministic polynomial time algorithms to solve them. In this paper, we improve the LVP algorithm in local fields. The modified LVP algorithm is a deterministic polynomial time algorithm when the field is totally ramified and <i>p</i> is a polynomial in the rank of the input lattice. We utilize this algorithm to attack the above schemes so that we are able to forge a valid signature of any message and decrypt any ciphertext. Although these schemes are broken, this work does not mean that <i>p</i>-adic lattices are not suitable in constructing cryptographic primitives. We propose some possible modifications to avoid our attack at the end of this paper.\u0000</p>","PeriodicalId":11130,"journal":{"name":"Designs, Codes and Cryptography","volume":"69 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143640437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A new framework for fast homomorphic matrix multiplication","authors":"Xiaopeng Zheng, Hongbo Li, Dingkang Wang","doi":"10.1007/s10623-025-01614-y","DOIUrl":"https://doi.org/10.1007/s10623-025-01614-y","url":null,"abstract":"<p>Homomorphic encryption (HE) is one of the mainstream cryptographic tools used to enable secure outsourced computation. A typical task is secure matrix computation, which is a fundamental operation used in various outsourced computing applications such as statistical analysis and machine learning. In this paper, we present a new framework for secure multiplication of two matrices with size <span>(r times s)</span> and <span>(s times t)</span> respectively, which requires only <span>(O(log n))</span> basic homomorphic operations if <span>(rst le n)</span>, where <i>n</i> is dimension of the polynomial ring used in RLWE encryption. Our method was implemented in HElib using the BGV scheme. Experimental results show that the new framework has significant advantage in efficiency when <span>(rst le n)</span>. In this case, the new framework is 1.2 to 106.8 times faster than exiting algorithms in experiments.</p>","PeriodicalId":11130,"journal":{"name":"Designs, Codes and Cryptography","volume":"41 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143627620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Resolution of the exceptional APN conjecture in the Gold degree case","authors":"Carlos Agrinsoni, Heeralal Janwa, Moises Delgado","doi":"10.1007/s10623-025-01607-x","DOIUrl":"https://doi.org/10.1007/s10623-025-01607-x","url":null,"abstract":"<p>A function <span>(f: {mathbb {F}}_q rightarrow {mathbb {F}}_q)</span>, is called an <i>almost perfect nonlinear </i> (APN) if <span>(f(X+a)-f(X) =b)</span> has at most 2 solutions for every <span>(b,a in {mathbb {F}}_q)</span>, with <i>a</i> nonzero. Furthermore, it is called an exceptional APN if it is an APN on infinitely many extensions of <span>({mathbb {F}}_q)</span>. These problems are equivalent to finding rational points on the corresponding variety <span>({mathcal {X}}_f:=phi _f(X,Y,Z)=0)</span>. The Lang–Weil, Deligne, and Ghorpade–Lachaud bounds help solve these problems when <span>(phi _f)</span> contains an absolutely irreducible factor in the defining field. The exceptional monomial APN functions had been classified up to CCZ equivalence by Hernando and McGuire (J Algebra 343:78–92, 2011), proving the conjecture of Janwa, Wilson, and McGuire (JMW) (1993, 1995). The main tools used were the computation and classification of the singularities of <span>({mathcal {X}}_f)</span> and the algorithm of JMW for the absolute irreducibility testing using Bezout’s Theorem. Aubry et al. (2010) conjectured that the only exceptional APN functions of odd degree up to CCZ equivalence are the Gold <span>((2^k+1))</span> and the Kasami-Welch <span>((2^{2k}-2^k+1))</span> monomial functions. Here, we settle the first case (Theorem 20). We also prove a part of a conjecture on exceptional crooked functions. One of the main tools in our proofs is our new absolute irreducibility criterion (Theorem 9).</p>","PeriodicalId":11130,"journal":{"name":"Designs, Codes and Cryptography","volume":"22 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143618460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ling Song, Qinggan Fu, Qianqian Yang, Yin Lv, Lei Hu
{"title":"Generalized impossible differential attacks on block ciphers: application to SKINNY and ForkSKINNY","authors":"Ling Song, Qinggan Fu, Qianqian Yang, Yin Lv, Lei Hu","doi":"10.1007/s10623-025-01611-1","DOIUrl":"https://doi.org/10.1007/s10623-025-01611-1","url":null,"abstract":"<p>Impossible differential cryptanalysis is a crucial cryptanalytical method for symmetric ciphers. Given an impossible differential, the key recovery attack typically proceeds in two steps: generating pairs of data and then identifying wrong keys using the guess-and-filtering method. At CRYPTO 2023, Boura <i>et al.</i> first proposed a new key recovery technique—the differential meet-in-the-middle attack, which recovers the key in a meet-in-the-middle manner. Inspired by this technique, we incorporate the meet-in-the-middle technique into impossible cryptanalysis and propose a generic impossible differential meet-in-the-middle attack (<span>IDMA</span>) framework. We apply <span>IDMA</span> to block ciphers <span>SKINNY</span>, <span>SKINNYe</span>-v2, and <span>ForkSKINNY</span> and achieve remarkably efficient attacks. We improve the impossible differential attack on <span>SKINNY</span>-<i>n</i>-3<i>n</i> by 2 rounds in the single-tweakey setting and 1 round in the related-tweakey setting. For <span>SKINNYe</span>-v2, the impossible differential attacks now can cover 2 more rounds in the related-tweakey setting and the first 23/24/25-round attacks in the single-tweakey model are given. For <span>ForkSKINNY</span>-<i>n</i>-3<i>n</i>, we improve the attacks by 2 rounds in the limited setting specified by the designers and 1 round in relaxed settings. These results confirm that the meet-in-the-middle technique can result in more efficient key recovery, reaching beyond what traditional methods can achieve on certain ciphers.</p>","PeriodicalId":11130,"journal":{"name":"Designs, Codes and Cryptography","volume":"183 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143618461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Galois subcovers of the Hermitian curve in characteristic p with respect to subgroups of order dp with $$dnot =p$$ prime","authors":"Arianna Dionigi, Barbara Gatti","doi":"10.1007/s10623-025-01613-z","DOIUrl":"https://doi.org/10.1007/s10623-025-01613-z","url":null,"abstract":"<p>A problem of current interest, also motivated by applications to Coding theory, is to find explicit equations for <i>maximal</i> curves, that are projective, geometrically irreducible, non-singular curves defined over a finite field <span>(mathbb {F}_{q^2})</span> whose number of <span>(mathbb {F}_{q^2})</span>-rational points attains the Hasse-Weil upper bound <span>(q^2+2mathfrak {g}q+1)</span> where <span>(mathfrak {g})</span> is the genus of the curve <span>(mathcal {X})</span>. For curves which are Galois covered of the Hermitian curve, this has been done so far ad hoc, in particular in the cases where the Galois group has prime order and also when has order the square of the characteristic. In this paper we obtain explicit equations of all Galois covers of the Hermitian curve with Galois group of order <i>dp</i> where <i>p</i> is the characteristic of <span>(mathbb {F}_{q^2})</span> and <i>d</i> is a prime other than <i>p</i>. We also compute the generators of the Weierstrass semigroup at a special <span>(mathbb {F}_{q^2})</span>-rational point of some of the curves, and discuss some possible positive impacts on the minimum distance problems of AG-codes.\u0000</p>","PeriodicalId":11130,"journal":{"name":"Designs, Codes and Cryptography","volume":"68 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143618462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
John Baena, Daniel Cabarcas, Sharwan K. Tiwari, Javier Verbel, Luis Villota
{"title":"Admissible parameters for the Crossbred algorithm and semi-regular sequences over finite fields","authors":"John Baena, Daniel Cabarcas, Sharwan K. Tiwari, Javier Verbel, Luis Villota","doi":"10.1007/s10623-025-01610-2","DOIUrl":"https://doi.org/10.1007/s10623-025-01610-2","url":null,"abstract":"<p>Multivariate public key cryptography (MPKC) is one of the most promising alternatives to build quantum-resistant signature schemes, as evidenced in NIST’s call for additional post-quantum signature schemes. The main assumption in MPKC is the hardness of the Multivariate Quadratic (MQ) problem, which seeks for a common root to a system of quadratic polynomials over a finite field. Although the Crossbred algorithm is among the most efficient algorithms to solve MQ over small fields, its complexity analysis stands on shaky ground. In particular, it is not clear for what parameters it works and under what assumptions. In this work, we provide a rigorous analysis of the Crossbred algorithm over any finite field. We provide a complete explanation of the series of admissible parameters proposed in previous literature and explicitly state the regularity assumptions required for its validity. Moreover, we show that the series does not tell the whole story, hence we propose an additional condition for Crossbred to work. Additionally, we define and characterize a notion of regularity for systems over a small field, which is one of the main building blocks in the series of admissible parameters.</p>","PeriodicalId":11130,"journal":{"name":"Designs, Codes and Cryptography","volume":"11 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143599669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}