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Package management systems play an essential role in pursuing systems dependability by ensuring that software is correctly installed and kept up-to-date according to vendor-defined installation policies. Circumventing such policies could make the system unhealthy and insecure and can constitute a serious security threat. In many application scenarios, e.g., distribution of commercial software, the confidentiality of the software must be guaranteed against non-authorized players. In some cases, the installation policy itself is considered a sensitive information, e.g., when it reveals required hardware in military contexts. In this paper we address the problem of strongly enforcing software dependencies in package management systems, to prevent that a malicious user forces the system to install any package despite its requirements are not completely fulfilled. The enforcement is strong in the sense that the encrypted software package cannot be even decrypted if the dependencies are not satisfied. Once a new package is decrypted and installed, our protocol non-interactively updates the key material on the target device. This key update will allow the decryption of further packages that depend on the newly installed one. We further present “policy-hiding” variants of our protocol. Finally we provide an experimental evaluation of the system performance

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User authentication schemes have been a key research topic in the field of data security for decades. Such schemes are evaluated according to at least two parameters: security and usability. Since a number of secure and usable authentication schemes are available, each institution can select the scheme that is considered to be most appropriate for its security policy. Such a per-site system selection has the following feature: each site has to authorize each user that tries to access its resources. In a world in which users mobility is growing, the feature we have just described forces a huge overhead; both from the site's viewpoint and the users' viewpoint, since each user needs to store different credentials for each site she accesses to.Federated authentication allows users to use their home authentication credentials for gaining access to other institutions services while moving among different institutions. Different federated authentication systems have been designed and implemented. Despite simplified users mobility, one key problem in this area is that, often, different authentication systems do not cooperate or provide a limited interoperability. In this paper we discuss the problem of achieving full interoperability among Federated Identity Management Systems and present, as proof-ofconcept, a solution to allow full communication between two federated authentication systems, Shibboleth a de facto standard in this context, and PAPI (Point of Access to Providers of Information). Such a solution leverages an intermediate bridge which joins both federations and features protocols translation during cross-federation Authentication/Authorization (AA) sessions.

Digital signatures have been proposed by several researchers as a way of preventing execution of malicious code. In this paper we propose a general architecture for performing the signature verification as part of the kernel execution process. The proposed architecture does not require any change in the interpreters used to execute code and it can accommodate any executable format. We also report on our implementation for the Linux operating system that focuses on ELF and script executables. Experimental results show that our solution is of potential interest as virtually no slowdown is experienced in the execution.