The Internet of Things (IoT) nodes consist of sensors that collect environmental data and then perform data exchange with surrounding nodes and gateways. Cybersecurity attacks pose a threat to the data security that is being transmitted in any IoT network. Cryptographic primitives are widely adopted to address these threats; however, the substantial computation demands limit their applicability in the IoT ecosystem. In addition, each IoT node varies with respect to the area and throughput (TP) requirements, thus demanding flexible implementation for encryption/decryption processes. To solve these issues, this work implements the NIST lightweight cryptography standard, Ascon, on a SAED 32 nm process design kit (PDK) library by employing loop folded, loop unrolled and fully unrolled architectures. The fully unrolled architecture can achieve the highest TP but at the cost of higher area utilisation. Unrolling by a lower factor results in lower area implementations, enabling the exploration of design space to tackle the trade-off between area and TP performance of the design. The implementation results show that, for loop folded architecture, Ascon-128 and Ascon-128a require 36.7k $$\upmu \textrm{m}^{2}$$μ m 2 and 38.5k $$\upmu \textrm{m}^{2}$$μ m 2 chip area, respectively compared to 277.1k $$\upmu \textrm{m}^{2}$$μ m 2 and 306.6k $$\upmu \textrm{m}^{2}$$μ m 2 required by their fully unrolled implementations. The proposed implementation strategies can adjust the number of rounds to accommodate the varied requirements of IoT ecosystems. An implementation with an open-source 45 nm PDK library is also undertaken for enhanced generalization and reproducibility of the results.

Post-quantum multivariate public key cryptography (MPKC) schemes resist quantum threats but require heavy operations, such as rejection sampling, which challenge resource-limited devices. Prior hardware designs have addressed various aspects of MPKC signature generation. However, rejection sampling remains largely unexplored in such contexts. This paper presents RejSCore, a lightweight hardware accelerator for rejection sampling in post-quantum cryptography. It specifically targets the QR-UOV scheme, which is a prominent candidate under the second-round of the National Institute of Standards and Technology (NIST) additional digital signature standardization process. The architecture includes an AES-CTR-128-based pseudorandom number generator. Moreover, a lightweight iterative method is employed in rejection sampling, offering reduced resource consumption and area overhead while slightly increasing latency. The performance of RejSCore is comprehensively evaluated on Artix-7 FPGAs and 65 nm CMOS technology using the Area-Delay Product (ADP) and Power-Delay Product (PDP). On Artix-7 and 65 nm CMOS, RejSCore achieves an area of 2042 slices and 464,866~$μm^2$, with operating frequencies of 222 MHz and 565 MHz, respectively. Using the QR-UOV parameters for security level I ($q = 127$, $v = 156$, $m = 54$, $l = 3$), the core completes its operation in 8525 clock cycles. The ADP and PDP evaluations confirm RejSCore's suitability for deployment in resource-constrained and security-critical environments.

Most of the healthcare systems electronics medical records (EMRs) are inefficient , and innovation in this domain is slow. Recently, researchers have proposed distributed EMRs using blockchain, in which healthcare system medical data of patients is publicly available for doctors and researchers to improve health quality of patients. Patient medical data are very private information, but blockchain does not provide full anonymity to medical data in distributed EMR of health-care systems. To overcome this issue, this paper presents an application scenario of distributed healthcare record and medical network (DHRMN), in which we make blockchain fully anonymous by utilizing the equality test property of Public Key Encryption with Equality Test (PKEET). However, most existing PKEET schemes have two main issues: (1) Once a server gets the trapdoor from a user to perform equality test, then the server can perform equality test on all ciphertexts of that user without further authorization; (2) Previous schemes require significant computation cost to perform equality test because they used bilinear pairing to perform equality test. These aforementioned two issues of PKEET might lead to privacy leakage or make DHRMN slow. Therefore, this paper presents the first secure lightweight public key encryption with equality test (LW-PKEET), where each trapdoor can only be used to perform the equality test on a particular ciphertext of any user, and to improve the performance, bilinear pairing operation is not used in key generation, encryption, decryption, trapdoor or equality test procedure of the proposed scheme. Moreover, we prove that the security of our LW-PKEET scheme is one-way secure against chosen ciphertext attacks (OW-CCA) in the random oracle model (ROM) under the Computational Diffie-Hellman (CDH) assumption.