As the Internet of Things (IoT) industry advances, the imperative to secure IoT devices has become increasingly critical. Current practices in both industry and academia advocate for the enhancement of device security through key installation. However, it has been observed that, in practice, IoT vendors frequently assign shared keys to batches of devices. This practice can expose devices to risks, such as data theft by attackers or large-scale Distributed Denial of Service (DDoS) attacks. To address this issue, our intuition is to assign a unique key to each device. Unfortunately, this strategy proves to be highly complex within the IoT context, as existing keys are typically hardcoded into the firmware, necessitating the creation of bespoke firmware for each device. Furthermore, correct pairing of device keys with their respective devices is crucial. Errors in this pairing process would incur substantial human and temporal resources to rectify and require extensive communication between IoT vendors, device manufacturers, and cloud platforms, leading to significant communication overhead. To overcome these challenges, we propose the OTA-Key scheme. This approach fundamentally decouples device keys from the firmware features stored in flash memory, utilizing an intermediary server to allocate unique device keys in two distinct stages and update keys. We conducted a formal security verification of our scheme using ProVerif and assessed its performance through a series of evaluations. The results demonstrate that our scheme is secure and effectively manages the large-scale distribution and updating of unique device keys. Additionally, it achieves significantly lower update times and data transfer volumes compared to other schemes.

翻译：随着物联网（IoT）行业的快速发展，保障物联网设备的安全性变得日益关键。当前工业界和学术界的普遍做法是通过密钥安装来增强设备安全性。然而，实践中发现，物联网供应商经常为批量设备分配共享密钥。这种做法会使设备面临诸多风险，例如攻击者窃取数据或发起大规模分布式拒绝服务（DDoS）攻击。为解决这一问题，我们的基本思路是为每台设备分配唯一密钥。遗憾的是，该策略在物联网场景中实施极为复杂，因为现有密钥通常被硬编码在固件中，需要为每台设备定制专用固件。此外，确保设备密钥与其对应设备的正确配对至关重要。配对过程中的错误将耗费大量人力与时间资源进行纠正，并需要物联网供应商、设备制造商与云平台之间进行大量通信，导致显著的通信开销。为克服这些挑战，我们提出了OTA-Key方案。该方法从根本上将设备密钥与存储在闪存中的固件特性解耦，利用中间服务器在两个独立阶段分配唯一设备密钥并更新密钥。我们使用ProVerif对本方案进行了形式化安全验证，并通过一系列评估测试了其性能。结果表明，本方案具有安全性，能有效管理大规模唯一设备密钥的分发与更新。此外，与其他方案相比，本方案实现了显著更低的更新时间和数据传输量。