由于受到系统资源和实时性的限制，对于嵌入式实时系统的安全扩展很难延用通用计算机系统的安全设计方法，因此需要对其进行专门的研究。为了在确保实时性的前提下使嵌入式实时系统的安全性达到最优，本文提出了一套完整的安全设计方法，包括安全任务图模型和安全评估模型，在此基础上，又提出了一种基于整数线性规划的安全策略优化生成方法ILPOS。该安全策略优化生成方法同时解决了安全算法选择和实时可调度性检测两方面的问题，克服了一般分阶段优化方法的不足，从而充分地利用系统可用时间来实现安全扩展。仿真实验结果表明，与传统的启发式安全设计算法相比，ILPOS方法在各种实时性约束条件下都能有效地提高系统的安全性。

Due to system resources and realtime constraints，the security design methods for general computing systems are not fit for the realtime embedded systems,so,it is necessary to study the special design method. To obtain the optimal security of embedded systems under realtime constraints,a complete set of security design methods which include the securityrelated task graph model and the security evaluation model are proposed in this paper. Based on these,an ILP based optimal security strategy generation method named ILPOS is also proposed. This method can select security algorithms and detect the realtime schedulability simultaneously. That is more efficient than the phased coupled optimization methods,therefore,it can make full use of the system time for security extension. The experimental results show that ILPOS can improve the system security efficiently under various time constraints compared with the traditional heuristic algorithms.