Cloud computing is an emerging computing paradigm in IT industries. The wide adoption of cloud computing is raising concerns about management of data in the cloud. Access control and data security are two critical issues of cloud computing. Time-efficient secure access control (TESAC) model is a new data access control scheme which can minimize many significant problems. This scheme has better performance than other existing models in a cloud computing environment. TESAC is attracting more and more attentions from industries. Hence, the reliability of TESAC becomes extremely important. In this paper, we apply Communication Sequential Processes (CSP) to model TESAC, as well as their security properties. We mainly focus on its data access mechanism part and formalize it in detail. Moreover, using the model checker Process Analysis Toolkit (PAT), we have verified that the TESAC model cannot assure the security of data with malicious users. For the purpose of solving this problem, we introduce a new method similar to digital signature. Our study can improve the security and robustness of the TESAC model.

中文翻译：

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使用 CSP 对 TESAC 进行形式化和验证

云计算是 IT 行业新兴的计算范式。云计算的广泛采用引起了人们对云中数据管理的担忧。访问控制和数据安全是云计算的两个关键问题。时间高效的安全访问控制（TESAC）模型是一种新的数据访问控制方案，可以最大限度地减少许多重大问题。该方案在云计算环境中比其他现有模型具有更好的性能。TESAC越来越受到业界的关注。因此，TESAC 的可靠性变得极为重要。在本文中，我们将通信顺序过程 (CSP) 应用于对 TESAC 及其安全属性进行建模。我们主要关注其数据访问机制部分并对其进行详细形式化。此外，使用模型检查器 Process Analysis Toolkit (PAT)，我们已经验证，TESAC 模型无法保证恶意用户的数据安全。为了解决这个问题，我们引入了一种类似于数字签名的新方法。我们的研究可以提高 TESAC 模型的安全性和鲁棒性。