The security of highly resource constrained applications is often viewed in the literature from a single aspect of a specific cryptographic primitive. More precisely, most of the proposed lightweight cryptographic primitives focus on providing a single functionality within the available hardware area dedicated for security purposes. In this paper, we argue that for such applications, a cryptographic primitive that follows the cryptographic minimal design strategy maybe the only realistically adopted security solution where there is a constrained GE budget for all security functionalities. Indeed, it is reasonable, if not desirable, for the adopted cryptographic design to have well justified building components and to provide minimal overhead for multiple cryptographic functionalities including encryption, hashing, authentication, and pseudorandom bit generation. Following such a strategy, we propose the sLiSCP family of lightweight cryptographic permutations which employs two of the most hardware efficient and extensively cryptanalyzed constructions, namely a 4-subblock Type-2 Generalized Feistel-like Structure (GFS) and round-reduced unkeyed Simeck. In addition to the hardware efficiency, we follow restrictive security design goals which enable us to provide resistance against differential and linear cryptanalysis, as well as guaranteed resistance to diffusion-based, algebraic, and self-symmetry distinguishers, and accordingly, we claim that there exist no structural distinguishers for sLiSCP-b with a complexity below 2b=2 where b is the state size. Moreover, we present the sLiSCP duplex sponge mode to illustrate how the permutations can be used in a unified design that provides (authenticated) encryption, hashing, and pseudorandom bit generation functionalities. Finally, we report two efficient parallel hardware implementations for the sLiSCP unified duplex sponge mode when using sLiSCP-192 (resp. sLiSCP-256) in CMOS 65 nm ASIC with area of 2289 (resp. 3039) GE and a throughput of 29.62 (resp. 44.44) kbps, and their areas in CMOS 130 nm are 2498 (resp. 3319) GE.

The emerging areas in which highly resource constrained devices are interacting wirelessly to accomplish tasks have led manufacturers to embed communication systems in them. Tiny low-end devices such as sensor networks nodes and Radio Frequency Identification (RFID) tags are of particular importance due to their vulnerability to security attacks, which makes protecting their communication privacy and authenticity an essential matter. In this work, we present a lightweight do-it-all cryptographic design that offers the basic underlying functionalities to secure embedded communication systems in tiny devices. Specifically, we revisit the design approach of the sLiSCP family of lightweight cryptographic permutations, which was proposed in SAC 2017. sLiSCP is designed to be used in a unified duplex sponge construction to provide minimal overhead for multiple cryptographic functionalities within one hardware design. The design of sLiSCP follows a 4-subblock Type-2 Generalized Feistel-like Structure (GFS) with unkeyed round-reduced Simeck as the round function, which are extremely efficient building blocks in terms of their hardware area requirements. In S L I SCP-light, we tweak the GFS design and turn it into an elegant Partial Substitution-Permutation Network construction, which further reduces the hardware areas of the S L I SCP permutations by around 16% of their original values. The new design also enhances the bit diffusion and algebraic properties of the permutations and enables us to reduce the number of steps, thus achieving a better throughput in both the hashing and authentication modes. We perform a thorough security analysis of the new design with respect to its diffusion, differential and linear, and algebraic properties. For S L I SCP-light-192, we report parallel implementation hardware areas of 1,820 (respectively, 1,892)GE in CMOS 65 nm (respectively, 130 nm ) ASIC. The areas for S L I SCP-light-256 are 2,397 and 2,500GE in CMOS 65 nm and 130 nm ASIC, respectively. Overall, the unified duplex sponge mode of S L I SCP-light-192, which provides (authenticated) encryption and hashing functionalities, satisfies the area (1,958GE), power (3.97μ W ), and throughput (44.4kbps) requirements of passive RFID tags.