# Rapidly Deployable IoT Architecture with Data Security: Implementation and Experimental Evaluation
## 2 Related Works  
### Encryption Algorithms  
Encryption algorithms can be broadly classified into three different types, asymmetric encryption, symmetric encryption, and hash functions. Although asymmetric cryptographic algorithms are flexible, they require higher power, larger storage and consume more power, which renders them unsuitable for securing IoT applications. Symmetric cryptographic encryption includes stream and block ciphers, which are faster and use simple fast operations, making them suitable for IoT applications. Stream ciphers are fast but are suited for streaming data, whereas block ciphers are more flexible in terms of application. Several of such lightweight block ciphers have been proposed to secure resource constrained devices in IoT applications. [PERSON] et al. assessed various security schemes and power consumption by Wireless Sensor Network (WSN) protocols [25]. The WSN nodes feed the data to the base station (BS), where the data is processed, and relayed to the cloud if any further processing is required. [PERSON] et al. simulated the encryption and decryption (AES algorithm) overhead in microseconds [26]. They discussed routing protocols, characteristics, limitations, vulnerabilities, and countermeasures. [PERSON] et al. implemented and evaluated block ciphers on 8-bit, 16-bit and 32-bit microcontrollers focusing on the widely used algorithm tinyAES and others suitable for embedded platforms [27]. [PERSON] et al. [28] stated that traditional cryptographic algorithms use a static structure, which requires several rounds of computation, adding significant overhead on execution time and constraint on computational resources. They further stated that the problem is compounded for multimedia data because the algorithms have stringent quality of service requirements. They offered a dynamic cipher structure, which minimizes the rounds to a single one without compromising randomness and security. In [29], [PERSON] et al. provided a list of algorithms and cryptanalysis against them. The author split lightweight cryptography into two groups namely, ultra-lightweightcryptography and ubiquitous cryptography. The authors provided design constraints that make an algorithm lightweight in terms of hardware and software. They also provided a benchmark for assessing good performance on a given platform. AES is a widely-used block cipher for security in IoT applications such as IEEE802.15.4, LoRaWAN, Zigbee, Sigfox, ZWave, and has readily available hardware accelerators built into commercial products. When code size and Random Access Memory (RAM) space is not of concern, AES is a strong candidate for providing security to small devices [15; 16; 17; 18]. However, AES implementation in software introduces time delay in data processing and transmission, and increases power and energy consumption. As such, researchers have custom designed AES hardware accelerators for implementation in portable IoT applications [30; 31], that is often not feasible for rapid deployment of IoT applications. Another alternative is using reprogrammable Field Programmable Gate Arrays (FPGA), but requires additional modules such as data-converters that are often not built-in. Optimized serial architectures like 8-b architectures for hardware implementation of AES are suitable for constraint devices as they require less area and energy but yield lower throughput. Another approach to solving the issue of securing resource constrained devices in IoT is assessing the feasibility of ultra-lightweight block ciphers such as SIMON and SPECK [19], PRESENT [21], and CLEFIA [32]. SIMON is a versatile lightweight block cipher based on Feistal networks, tailored for hardware implementation in resource constrained devices. Different datapath architectures for SIMON have been proposed and studied, which focus on area [33; 34], latency [34], throughput [31; 34], energy efficiency [34], and security [34].