In this study, with an FPGA-board using VHDL, we designed a secure chaos-based stream cipher (SCbSC), and we evaluated its hardware implementation performance in terms of computational complexity and its security. The fundamental element of the system is the proposed secure pseudo-chaotic number generator (SPCNG). The architecture of the proposed SPCNG includes three first-order recursive filters, each containing a discrete chaotic map and a mixing technique using an internal pseudo-random number (PRN). The three discrete chaotic maps, namely, the 3D Chebyshev map (3D Ch), the 1D logistic map (L), and the 1D skew-tent map (S), are weakly coupled by a predefined coupling matrix M. The mixing technique combined with the weak coupling technique of the three chaotic maps allows preserving the system against side-channel attacks (SCAs). The proposed system was implemented on a Xilinx XC7Z020 PYNQ-Z2 FPGA platform. Logic resources, throughput, and cryptanalytic and statistical tests showed a good tradeoff between efficiency and security. Thus, the proposed SCbSC can be used as a secure stream cipher.

The recent expansion of the Internet of Things is creating a new world of smart devices in which security implications are very significant. Besides the claimed security level, the IoT devices are usually featured with constrained resources, such as low computation capability, low memory, and limited battery. Lightweight cryptographic primitives are proposed in the context of IoT while considering the trade-off between security guarantee and good performance. In this paper, we present optimized hardware, lightweight cryptographic designs, of 32-bit datapath, LED 64/128, SIMON 64/128, and SIMECK 64/128 algorithms, for constrained devices. Our proposed designs are investigated on Spartan-3, Spartan-6, and Zynq-7000 FPGA platforms in terms of area, speed, efficiency, and power consumption. The proposed designs achieved a high throughput up to 891.99 Mbps, 838.95 Mbps, and 210.13 Mbps for SIMECK 64/128, SIMON 64/128, and LED 64/128 on Zynq-7000, respectively. A deep comparison between our three proposed designs is elaborated on different FPGA families for adequate FPGAs-based application deployment. Test results and security analysis show that not only can our proposed designs achieve good encryption results with high performance and a low reduced cost but also they are secure enough to resist statistical attacks.

This work proposes a new secure chaos-based encryption/decryption system, operating in cipher block chaining (CBC) mode, and analyze its performance. The cryptosystem includes a robust pseudorandom number generator of chaotic sequences (PRNG-CS). A strong chaos-based S-box is proposed to perform a circular substitution operation (confusion process). This PRNG-CS consists of four discrete 1-D chaotic maps, weakly coupled by a predefined coupling matrix M, to avoid, on the one hand, the divide-and-conquer attack and, on the other hand, to improve the generated sequence’s randomness and lengths. The noun is also used in the construction of the S-box. Moreover, a 2-D modified cat map and a horizontal addition diffusion (HAD) preceded by a vertical addition diffusion (VAD) are introduced to perform the diffusion process. The security analysis and numerous simulation results of the main components (PRNG-CS and S-box) as well as the whole cryptosystem reveal that the proposed chaos-based cryptosystem holds up against various types of statistical and cryptographic attacks.

The Internet of Things is changing all sectors such as manufacturing, agriculture, city infrastructure, and the automotive industry. All these applications ask for secure processors that can be embedded in the IoT devices. Furthermore, these devices are restricted in terms of computing capabilities, memory, and power consumption. A major challenge is how to meet the need for security in such resource-constrained devices. This paper presents a customized version of LEON3, the ReonV RISCV (Reduced Instruction Set Computer-five) processor, dedicated for IoT applications that has strong effective security mechanisms built in at the design stage. Firstly, efficient lightweight cipher designs are elaborated and validated. Then, the proposed cryptographic instructions (PRESENT and PRINCE) are integrated into the default instruction set architecture of the ReonV processor core. The instruction set extensions (ISE) of lightweight cipher modules can be instantiated in software routines exactly as the instructions of the base architecture. A single instruction is needed to implement a full lightweight cryptographic instruction. The customized ReonV RISCV processor is implemented on a Xilinx FPGA platform and is evaluated for Slice LUTs plus FF-pairs, frequency, and throughput. Obtained results show that our proposed concepts not only can achieve good encryption results with high performance and reduced cost but also are secure enough to resist against the most common attacks.

In this paper, we come up with three secure chaos-based stream ciphers, implemented on an FPGA board, for data confidentiality and integrity. To do so, first, we performed the statistical security and hardware metrics of certain discrete chaotic map models, such as the Logistic, Skew-Tent, PWLCM, 3D-Chebyshev map, and 32-bit LFSR, which are the main components of the proposed chaotic generators. Based on the performance analysis collected from the discrete chaotic maps, we then designed, implemented, and analyzed the performance of three proposed robust pseudo-random number generators of chaotic sequences (PRNGs-CS) and their corresponding stream ciphers. The proposed PRNGs-CS are based on the predefined coupling matrix M. The latter achieves a weak mixing of the chaotic maps and a chaotic multiplexing technique or XOR operator for the output function. Therefore, the randomness of the sequences generated is expanded as well as their lengths, and divide-and-conquer attacks on chaotic systems are avoided. In addition, the proposed PRNGs-CS contain polynomial mappings of at least degree 2 or 3 to make algebraic attacks very difficult. Various experimental results obtained and analysis of performance in opposition to different kinds of numerical and cryptographic attacks determine the high level of security and good hardware metrics achieved by the proposed chaos system. The proposed system outperformed the state-of-the-art works in terms of high-security level and a high throughput which can be considered an alternative to the standard methods.

In order to improve security and efficiency, this study presents a novel lightweight encryption technique that makes use of chaotic systems. Our method creatively combines the new chaotic KLEIN_64 algorithm with the Keccak-256 hash function, offering a solid basis for producing initial values essential for causing chaotic maps during the encryption process. After a deep validation with rigorous NIST testing, our chaotic pseudo random generator, LAC, exhibits excellent reliability and cryptographic robustness. Furthermore, the complexity of the cryptographic round function is improved by incorporating a second chaotic pseudo random generator that combines chaotic LFSR and Skew Tent Maps, thereby fortifying security measures.Designed with resource-limited applications in mind, our approach ensures that the cryptosystem remains both lightweight and efficient, meeting the stringent constraints typical of such environments. The practical feasibility and performance of our approach are extensively evaluated through FPGA implementation on the Zybo 7Z010 platform. Our implementation achieves a remarkable throughput of 2.820 Gbps while maintaining optimal resource utilization and efficiency. Extensive experimental results confirm the superior security of our cryptosystem, with correlation tests, entropy measurement, and histogram analysis showcasing robustness against statistical attacks. Moreover, the cryptosystem shows little fluctuation in the Unified Average Changing Intensity (UACI) and Non-Linear Pixel Change Rate (NPCR), confirming its resistance to differential attacks. Overall, our technique advances lightweight cryptography by providing a robust and efficient solution to modern cybersecurity challenges. In particular, our approach is well-suited for applications with limited resources, ensuring that security is maintained without compromising on performance or efficiency, thus fulfilling the needs of modern, constrained environments.