# SPIN: A Blockchain-Based Framework for Sharing COVID-19 Pandemic Information across Nations
## 6 Related Work
### Restraining COVID-19  
A wide range of papers have been published aiming to address the challenges related to COVID-19, mainly for diagnosing COVID-19 [51; 52; 53; 54], collecting public web data [55], contact tracing [56; 57; 58], social distancing [59; 60], vaccine delivery [61; 62; 63], and immunity passports [8; 9; 10; 11; 12; 13; 14; 15]. [PERSON] et al. [64] discussed the different use cases for blockchain technology to fight against COVID-19. Among the discussed use cases, our framework is closely related to those developing immunity passports. Several immunity passport papers [8; 9; 10] use self-sovereign identity (SSID) and verifiable credentials techniques to allow individuals to have full control over their private data, which is a desirable feature. However, these solutions require offering a mechanism, such as a mobile app, to allow individuals to practice this control, which may not be feasible for people across the globe. A closely related work to our approach [11] proposed using blockchain to share vaccination records for individuals. The authors of this work proposed using the users' iris template along with users' date of birth and gender to uniquely identify and authenticate individuals. To preserve the privacy of individuals' biometric information, the authors proposed using locality-sensitive hashing (LSH) to hash the iris templates before being written to the public ledger. Unlike our approach, which utilizes private messages, this approach relies on publishing health record information of individuals publicly in the blockchain, which makes these records accessible to anyone who acquires the user's iris template along with her date of birth and gender. This could potentially lead to the irreversible exposure of the users' private health records. In another work [13], the authors introduced a secure antibody certificate system (SecureABC) that uses a standard public-key signature scheme to ensure the binding and authenticity of certificates. A limitation of this work is that it relies on individual's photo and name for verification, which might not be sufficient. To tackle this issue, we proposed using biometric information such as fingerprints to uniquely identify individuals. [PERSON] et al. [8] provided a blockchain solution to issue and publish COVID-19 vaccine and test certificates using Ethereum smart contracts. These smart contracts execute actions, such as adding a test center, issuing a test result, and updating patient information. Data stored on the blockchain are mainly notifications about the execution of smart contracts. Private information is stored off-chain using the InterPlanetary File System (IPFS) with proxy re-encryption schemes. Moreover, it relies on SSID to allow individuals to have full control over their private information. Our proposed framework differs in various ways. First, it employs a permissioned blockchain, while Ethereum is a public blockchain that is more vulnerable to attacks and has lower throughput and scalability compared to permissioned blockchain [25]. Second, their proposed solution consists of several components that are a blockchain, SSID, and IPFS, which may not be easily adaptable across the globe. Third, our framework employs cancelable fingerprint templates to authenticate individuals. Their solution stores individuals' biometric information with their unique Ethereum address (EA) on-chain, but details are not provided. Fourth, our solution is more flexible as it allows peers to send any kind of public data in the form of key-value pairs, while their solution is limited to events about executed smart contracts. [PERSON] et al. [9] developed a mobile app to facilitate issuing and verifying COVID-19 test and vaccine certificates. Their solution is limited to sharing private data, which are test and vaccine certificates, and does not support sharing public data. It utilizes Verifiable Credentials to issue digital certificates and allow individuals to store their private documents on their phones or their preferred cloud providers.