Overview of SEPAR: A Lightweight Hybrid Cryptographic Algorithm for IoT
The paper presents an innovative lightweight hybrid encryption algorithm named SEPAR, specifically designed for Internet of Things (IoT) applications. The primary goal of SEPAR is to enhance cryptographic strength while optimizing performance across various system architectures, including microcontrollers frequently used in IoT devices.
Algorithm Design
SEPAR is constructed using a hybrid approach that combines the strengths of block ciphers and stream ciphers. It processes data using 16-bit blocks and employs a 256-bit master key. The algorithm integrates pseudo-random permutation and pseudo-random generator functions, which together fortify the cryptographic resistance of SEPAR against prevalent attacks such as linear and differential cryptanalysis.
The design thoughtfully balances security, cost, and performance, targeting IoT environments characterized by constrained resources and energy limitations. The selection of 16-bit S-boxes and efficient linear feedback shift registers (LFSR) aids in maintaining low computational overhead while ensuring robust non-linearity and entropy properties necessary for secure encryption.
Security Analysis
Comprehensive security tests affirm SEPAR's resilience against various cryptographic attacks, including algebraic and key-related vulnerabilities. The NIST statistical tests corroborate the randomness and unpredictability of SEPAR's output, which closely aligns with entropy standards set by established algorithms like AES.
Among the key features that enhance resistance to cryptographic attacks are SEPAR’s differential and linear properties, demonstrated through exhaustive analyses and documented tables presenting maximal probabilities and differential characteristic paths. SEPAR's algebraic resistance is ensured by employing S-boxes with a high algebraic degree, complicating potential algebraic attacks. Its hybrid structure further thwarts complementary attack strategies.
Implementation Results
The practical implementation of SEPAR was tested across platforms with varied architectures: 8-bit, 16-bit, and 32-bit systems. The implementation on 8-bit ATmega128L and 32-bit ARM LPC2129 microcontrollers highlights SEPAR's superior performance compared to widely recognized lightweight algorithms like PRESENT and BORON.
Significantly, SEPAR achieves notable improvement over existing algorithms in encryption efficiency. For instance, SEPAR exhibited 87.91% performance improvement over PRESENT on 8-bit microcontrollers, alongside a substantial 42.25% enhancement over BORON on ARM processors. These results are reflective of SEPAR’s architecture that favors speed and security without compromising device constraints in typical IoT scenarios.
Implications and Future Directions
The SEPAR algorithm provides a viable solution to cryptographic challenges in IoT environments, where resource efficiency and robust security are paramount. It offers promising improvements over traditional lightweight encryption standards, paving the way for more secure and efficient IoT implementations.
Future research could explore SEPAR's applicability to other environments with unique constraints, as well as its resilience against advanced attacks, including those targeting implementation. Additionally, extending SEPAR's application to real-world scenarios might involve developing further optimizations specific to proprietary IoT devices and platforms.
In summary, SEPAR stands out as a well-designed cryptographic tool that judiciously balances the intricate trade-offs between security, performance, and cost in the IoT paradigm, fostering enhanced cryptographic standards tailored to modern decentralized networks.
