## Forthcoming articles

### International Journal of Applied Cryptography

These articles have been peer-reviewed and accepted for publication but are pending final changes, are not yet published and may not appear here in their final order of publication until they are assigned to issues. Therefore, the content conforms to our standards but the presentation (e.g. typesetting and proof-reading) is not necessarily up to the Inderscience standard. Additionally, titles, authors, abstracts and keywords may change before publication. Articles will not be published until the final proofs are validated by their authors.

Forthcoming articles must be purchased for the purposes of research, teaching and private study only. These articles can be cited using the expression "in press". For example: Smith, J. (in press). Article Title. Journal Title.

Articles marked with this shopping trolley icon are available for purchase - click on the icon to send an email request to purchase.

Register for our alerting service, which notifies you by email when new issues are published online.

Articles marked with this Open Access icon are freely available and openly accessible to all without any restriction except the ones stated in their respective CC licenses.
We also offer which provide timely updates of tables of contents, newly published articles and calls for papers.
 International Journal of Applied Cryptography (4 papers in press) Regular Issues Efficient coding for secure computing with additively-homomorphic encrypted data   by Thijs Veugen Abstract: A framework is introduced for efficiently computing with encrypted data. We assume a semi-honest security model with two computing parties. Two different coding techniques are used with additively homomorphic encryption, such that many values can be put into one large encryption, and additions and multiplications can be performed on all values simultaneously. For more complicated operations such as comparisons and equality tests, bit-wise secret sharing is proposed as an additional technique that has a low computational and communication complexity, and which allows for precomputing. The framework is shown to significantly improve the computational complexity of state-of-the-art solutions on generic operations such as secure comparisons and secure set intersection. Keywords: packing; batching; homomorphic encryption; secure comparison; secure equality; secure set intersection; vector addition chain. Delegation-based conversion from CPA- to CCA-secure predicate encryption   by Mridul Nandi, Tapas Pandit Abstract: In 2011, Yamada et al. provided the generic delegation-based conversion and verifiability-based conversion from CPA- to CCA-secure attribute-based encryption (ABE). In 2012, Yamada et al. generalised the verifiability-based conversion from ABE (Yamada et al. 2011) to the predicate encryption (PE). In the aforementioned conversions, the decryption algorithm of the target CCA-secure PE scheme runs the decryption of the primitive CPA-secure PE scheme. In addition for verifiability-based conversions, the decryption algorithm of the target CCA-secure PE scheme has to perform the verifiability testing. We observe that for bilinear-pairing-based PE schemes, the cost of the verifiability testing is nearly equal to the cost of the CPA-decryption. So, the cost of CCA-decryption blows up to the double of the cost of CPA-decryption. Therefore, the conversion (CPA to CCA) based on delegation is mostly acceptable whenever the delegation-based conversion is available for the primitive PE scheme. In this paper, we investigate a generic delegation-based conversion from CPA- to CCA-secure predicate encryption schemes. Our conversion generalises the delegation-based conversion of Yamada et al., proposed in 2011, from ABE to PE. We show that our conversion captures many subclasses of PE, i.e., (hierarchical) inner-product encryption, (doubly-)spatial encryption and functional encryption for regular languages. Keywords: Predicate Encryption; Delegation; CPA to CCA Conversion. Dynamic MDS diffusion layers with efficient software implementation   by Mohammad Reza Mirzaee Shamsabad, S.M. Dehnavi Abstract: MDS (Maximum Distance Separable) matrices play a crucial role in symmetric ciphers as diffusion layers. Dynamic diffusion layers for software applications are less considered up to now. Dynamic (randomised) components could make symmetric ciphers more resistant against statistical and algebraic attacks. In this paper, after some theoretical investigation, we present a family of parametric $n \times n$ binary matrices $\mathcal{A}_\alpha$, $n=4t$, such that for $4^t$ many $\alpha \in \mathbb{F}_2^n$, the matrices $\mathcal{A}_{\alpha}$, $\mathcal{A}_{\alpha}^3 \oplus I$ and $\mathcal{A}_{\alpha}^7 \oplus I$ are non-singular. With the aid of the proposed family of matrices, some well-known diffusion layers, including the cyclic AES-like matrices and some recursive MDS diffusion layers could be made dynamic, at little extra cost in software. Then, we provide new families of MDS matrices which could be used as dynamic diffusion layers, using the proposed family of matrices. The implementation cost of every member in the presented families of MDS diffusion layers (except one cyclic family) is equal to its inverse. The proposed diffusion layers have a suitable implementation cost on a variety of modern processors. Keywords: MDS matrix; symmetric cipher; dynamic diffusion layer; branch number; software implementation. Computing the optimal Ate pairing over elliptic curves with embedding degrees 54 and 48 at the 256-bit security level   by Narcisse Bang Mbiang, Diego F. Aranha, Emmanuel Fouotsa Abstract: Owing to recent advances in the computation of discrete logarithms over finite fields, the Barreto-Lynn-Scott family of elliptic curves of embedding degree $48$ became suitable for instantiating pairing-based cryptography at the 256-bit security level. Observing the uncertainty around determining the constants that govern the best approach for computing discrete logarithms, Scott and Guillevic found it prudent to also consider pairing-friendly elliptic curves of embedding degree higher than $50$, and discovered a new family of elliptic curves with embedding degree $54$. This work aims at investigating the theoretical and practical cost of both the Miller algorithm and the final exponentiation in the computation of the optimal Ate pairing on the two aforementioned curves. Both our theoretical results, based on the operation counts of base-field operations, and our experimental observations collected from a real implementation, confirm that BLS48 curves remain the faster curves in the computation of the optimal Ate pairing at the 256-bit security level. We also implement the optimal Ate pairing on the two families of curves in the MAGMA software to ensure correctness of our formulas. Keywords: elliptic curves; pairing-friendly curves; optimal pairings; Miller loop; final exponentiation.