基于扩展LS的可信虚拟平台信任链分析

针对可信虚拟平台信任链的形式化分析问题,建立了包括虚拟机和虚拟信任根在内的可信虚拟平台完整的信任链模型,并详细定义其应满足的信任属性,通过扩展LS2,验证了可信虚拟平台信任链模型能够有条件地满足其正确性、唯一性。对实例系统分析表明本文所建立信任链模型的通用性及基于扩展LS2分析方法的有效性。     

跨平台的可信执行环境模块方案研究

针对现有TPM、MTM等可信计算模块不能跨平台使用,未考虑算法、协议、功能更新等问题,提出一种基于硬件的可信执行环境模块（TEEM, trusted execution environment module）架构,该架构利用ARM TrustZone技术构建一个运行在硬件安全隔离环境中的可信计算模块。该模块能够为多种平台提供可信计算功能,具备较强的移动性和便携性,并且允许用户根据需要灵活地配置、升级模块的功能和算法。设计并实现了基于TEEM架构的原型系统,原型系统的安全性分析和性能测试结果表明,TEEM能够为用户提供一个安全、稳定、高效的可信执行环境。     

基于可信芯片的平台身份证明方案研究

对基于可信第三方的平台身份证明方案进行了研究,提出了一种用证书和令牌标识可信计算平台并直接使用令牌证明平台身份的方案。与其他方案相比,该方案降低了证明过程的计算量和通信量,并且验证方验证平台身份的同时能够确认平台状态可信,获得了更高的安全性。利用协议组合逻辑证明了方案满足平台身份验证正确性和匿名性。原型系统实验结果表明,该方案平台身份证明效率高,特别适用于无线网络环境。     

TPM用户密钥命令安全性形式化分析

The Trusted Platform Module (TPM) is a dedicated hardware chip designed to provide a higher level of security for computing platform. All TPM functionalities are implemented in TPM commands to achieve specific security goals. We attempt to analyze the security properties of these commands, especially the key management API. Our study utilizes applied pi calculus to formalize the commands and determine how their security properties affect TPM key management. The attacker is assumed to call TPM commands without bounds and without knowing the TPM root key, expecting to obtain or replace the user key. The analysis goal in our study is to guarantee the corresponding property of API execution and the integrity of API data. We analyze the security properties of TPM commands with a process reduction method, identify the key-handle hijack attack on a TPM newly created key, and propose reasonable solutions to solve the problem. Then, we conduct an experiment involving a key-handle attack, which successfully replaces a user key with an attacker's key using malicious TPM software. This paper discloses the weakness of the relationship between the key handle and the key object. After the TPM software stack is compromised, the attacker can launch a key-handle attack to obtain the user key and even break into the whole storage tree of user keys.