The COVID-19 pandemic has emerged as a highly transmissible disease which has caused a disastrous impact worldwide by adversely affecting the global economy, health, and human lives. This sudden explosion and uncontrolled worldwide spread of COVID-19 has revealed the limitations of existing healthcare systems regarding handling public health emergencies. As governments seek to effectively re-establish their economies, open workplaces, ensure safe travels and progressively return to normal life, there is an urgent need for technologies that may alleviate the severity of the losses. This article explores a promising solution for secure Digital Health Certificate, called NovidChain, a Blockchain-based privacy-preserving platform for COVID-19 test/vaccine certificates issuing and verifying. More precisely, NovidChain incorporates several emergent concepts: (i) Blockchain technology to ensure data integrity and immutability, (ii) self-sovereign identity to allow users to have complete control over their data, (iii) encryption of Personally Identifiable Information to enhance privacy, (iv) W3C verifiable credentials standard to facilitate instant verification of COVID-19 proof, and (v) selective disclosure concept to permit user to share selected pieces of information with trusted parties. Therefore, NovidChain is designed to meet a high level of protection of personal data, in compliant with the GDPR and KYC requirements, and guarantees the user's self-sovereignty, while ensuring both the safety of populations and the user's right to privacy. To prove the security and efficiency of the proposed NovidChain platform, this article also provides a detailed technical description, a proof-of-concept implementation, different experiments, and a comparative evaluation. The evaluation shows that NovidChain provides better financial cost and scalability results compared to other solutions. More precisely, we note a high difference in time between operations (i.e., between 46% and 56%). Furthermore, the evaluation confirms that NovidChain ensures security properties, particularly data integrity, forge, binding, uniqueness, peer-indistinguishability, and revocation.

中文翻译：

---

NovidChain：基于区块链的 COVID-19 测试/疫苗证书隐私保护平台

COVID-19 大流行已成为一种高度传染性疾病，通过对全球经济、健康和人类生活产生不利影响，在全球范围内造成了灾难性影响。COVID-19 的这种突然爆发和不受控制的全球传播揭示了现有医疗保健系统在处理突发公共卫生事件方面的局限性。随着各国政府寻求有效地重建经济、开放工作场所、确保安全旅行并逐步恢复正常生活，迫切需要能够减轻损失严重性的技术。本文探讨了一种有前途的安全数字健康证书解决方案，称为 NovidChain，它是一个基于区块链的隐私保护平台，用于颁发和验证 COVID-19 测试/疫苗证书。更确切地说，NovidChain 融合了几个新兴概念：(i) 区块链技术确保数据完整性和不变性，(ii) 自我主权身份，允许用户完全控制他们的数据，(iii) 加密个人身份信息以增强隐私，(iv ) W3C 可验证凭证标准，以促进 COVID-19 证明的即时验证，以及 (v) 选择性披露概念，以允许用户与受信任方共享选定的信息片段。因此，NovidChain 旨在满足对个人数据的高水平保护，符合 GDPR 和 KYC 要求，在保证用户自主权的同时，确保人群安全和用户隐私权。为了证明提议的 NovidChain 平台的安全性和效率，本文还提供了详细的技术描述、概念验证实现、不同的实验和比较评估。评估表明，与其他解决方案相比，NovidChain 提供了更好的财务成本和可扩展性结果。更准确地说，我们注意到操作之间的时间差异很大（即，在 46% 和 56% 之间）。此外，评估确认 NovidChain 确保了安全属性，特别是数据完整性、伪造、绑定、唯一性、对等不可区分性和撤销。我们注意到操作之间的时间差异很大（即，在 46% 和 56% 之间）。此外，评估确认 NovidChain 确保了安全属性，特别是数据完整性、伪造、绑定、唯一性、对等不可区分性和撤销。我们注意到操作之间的时间差异很大（即，在 46% 和 56% 之间）。此外，评估确认 NovidChain 确保了安全属性，特别是数据完整性、伪造、绑定、唯一性、对等不可区分性和撤销。