German smart lock company slock.it filed a patent application in April of 2020 for a smart lock system that uses blockchain records and smart contract execution to verify a user and allow access into a room. Specifically, the system uses reservation information — check-in date, duration of stay, room type, payment — to control an IoT smart lock, which is useful for hotels and other property-sharing services. The use of blockchain benefits the hotel/host by securing the transaction; in addition, it also protects the guest by informing them if the hotel/host makes any changes to their reservation such as downgrading their room or changing the conditions of the stay. 

slock.it was acquired in July of 2019 by Blockchains, which focuses on using blockchain technology to enable smart city development. The company projects that it will break ground on its first smart city in Nevada in 2022. Smart locks will certainly be important in such an environment; other relevant blockchain-enabled IoT technologies include smart home connectivity, telecommunications management, and peer-to-peer digital cryptocurrency payment systems. You can view patent filings for these technologies and more on the Magic Number® Cryptocurrency Patent Radian®.