# SPCL: A Smart Access Control System That Supports Blockchain
## 8 Related Work  
In this section, we have compared and analyzed three categories of related work. The first category is a comparison of several similar intelligent access control solutions proposed previously. The second category is SPCL-related benchmark protocol comparison. The third category is a comparison of the differences in related solutions that support blockchain.  
At present, smart phones are becoming considerably popular and ubiquitous in our daily lives [13; 34]. With the widespread popularity of smart phones, the smart phone based applications have also gained growing attention. In this paper, we have built a prototype of SPCL, using a smart phone and a cloud server. SPCL can be applied to access control in intelligent buildings to enhance security and convenience. In the architecture presented by [PERSON] et al. [15], the mobile phone connects with the smart devices directly. Nevertheless, security mechanisms rely on the security of Bluetooth. In addition, the security solution is not quite flexible compared with SPCL. [PERSON] et al. [18] proposed a security protocol for smart lock systems, but this solution did not fully consider user privacy. [PERSON] et al. [21] used RFID tags to unlock the lock. However, the loss of the card will bring risks to the security of the smart lock. The smart disposable door lock system based on invisible touch sensors by [PERSON] et al. [22] is difficult to apply to hotels and other commercial occasions and lacks usability.  
In SPCL-related benchmark protocol, [PERSON] et al. [30] introduced an innovative access control scheme leveraging smart cards, albeit this approach has been critiqued for its vulnerability to attacks aimed at compromising long-term secrets. Similarly, the framework proposed by [PERSON] et al. [29], while ambitious, demonstrates limitations in warding off replay attacks and fails to establish mutual authentication, thereby undermining the security integrity of smart lock systems. In an intriguing deviation from conventional methods, [PERSON] et al. [28] ventured into the metaverse realm, proposing an authentication protocol utilizing smart glasses for server authentication, in contrast to the ubiquitous smartphone-based approaches. However, when benchmarked against the SPCL framework, it becomes evident that SPCL not only offers a more energy-efficient and cost-effective solution but also excels in usability without necessitating the deployment of additional Virtual Reality (VR) equipment. Moreover, the PSLA scheme [27], despite its tailored applicability to environments characterized by disparate computing capabilities, is deemed less conducive for smart door lock scenarios due to its inadequacy in offering perfect forward security and potential exposure of short-term secrets.  
Blockchain solutions have garnered widespread attention in recent years. In 2017, [PERSON] et al. [35] introduced a blockchain data sharing scheme for the healthcare sector. This system utilizes blockchain to store addresses (instead of actual health data) to maintain privacy and efficiency, allowing nodes to securely access and share health data. More recently, [PERSON] et al. [36] proposed a web3-based academic paper access control system for sharing papers. Due to the lack of blockchain support in current smart lock systems, SPCL provides a blockchain-enabled solution to provide safe and useful credentials for users using online hotel reservation systems.