As the development of Internet of Things (IoT), the data exchanged through the network has significantly increased. To secure the sensitive data with user’s personal information, it is necessary to encrypt the transmitted data. Since resource-constrained wireless devices are typically used for IoT services, it is required to optimize the performance of cryptographic algorithms which are computation-intensive tasks. In this paper, we present efficient implementations of ARX-based Korean Block Ciphers (HIGHT and LEA) with CounTeR (CTR) mode of operation, and CTR_DRBG, one of the most widely used DRBGs (Deterministic Random Bit Generators), on 8-bit AVR Microcontrollers (MCUs). Since 8-bit AVR MCUs are widely used for various types of IoT devices, we select it as the target platform in this paper. We present an efficient implementation of HIGHT and LEA by making full use of the property of CTR mode, where the nonce value is fixed, and only the counter value changes during the encryption. On our implementation, the cost of additional function calls occurred by the generation of look-up table can be reduced. With respect to CTR_DRBG, we identified several parts that do not need to be computed. Thus, precomputing those parts in offline and using them online can result in performance improvements for CTR_DRBG. Furthermore, we applied several optimization techniques by making full use of target devices’ characteristics with AVR assembly codes on 8-bit AVR MCUs. Our proposed table generation way can reduce the cost for building a precomputation table by around 6.7% and 9.1% in the case of LEA and HIGHT, respectively. Proposed implementations of LEA and HIGHT with CTR mode on 8-bit AVR MCUs provide 6.3% and 3.8% of improved performance, compared with the previous best results, respectively. Our implementations are the fastest compared to previous LEA and HIGHT implementations on 8-bit AVR MCUs. In addition, the proposed CTR_DRBG implementations on AVR provide better performance by 37.2% and 8.7% when the underlying block cipher is LEA and HIGHT, respectively.

中文翻译：

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在8位AVR微控制器上基于ARX的块密码的有效实现

随着物联网（IoT）的发展，通过网络交换的数据已大大增加。为了用用户的个人信息保护敏感数据，有必要对传输的数据进行加密。由于资源受限的无线设备通常用于物联网服务，因此需要优化加密算法的性能，这是计算密集型任务。在本文中，我们介绍了基于Cox（R）操作模式的基于ARX的韩语块密码（HIGHT和LEA）的有效实现，以及在8位上最广泛使用的DRBG（确定性随机位生成器）之一的CTR_DRBG。 AVR微控制器（MCU）。由于8位AVR MCU广泛用于各种类型的IoT设备，因此我们将其选择为目标平台。我们通过充分利用CTR模式的属性（在这种情况下，nonce值是固定的，并且在加密期间仅计数器值会发生变化）来提供HIGHT和LEA的有效实现。在我们的实现中，可以减少由于生成查询表而产生的其他函数调用的成本。关于CTR_DRBG，我们确定了几个不需要计算的部分。因此，离线地预先计算这些零件并在线使用它们可以提高CTR_DRBG的性能。此外，我们通过在8位AVR MCU上利用AVR汇编代码充分利用目标设备的特性，应用了多种优化技术。对于LEA和HIGHT，我们提出的表生成方式可以将构建预计算表的成本分别降低约6.7％和9.1％。与先前的最佳结果相比，在8位AVR MCU上采用CTR模式的LEA和HIGHT的拟议实施分别提供了6.3％和3.8％的改进性能。与以前在8位AVR MCU上执行LEA和HIGHT实施相比，我们的实施速度最快。此外，当基础块密码分别为LEA和HIGHT时，在AVR上提议的CTR_DRBG实现方案可提供37.2％和8.7％的更好性能。