Biblio

Many systems rely on passwords for authentication. Due to numerous accounts for different services, users have to choose and remember a significant number of passwords. Password-Manager applications address this issue by storing the user's passwords. They are especially useful on mobile devices, because of the ubiquitous access to the account passwords. Password-Managers often use key derivation functions to convert a master password into a cryptographic key suitable for encrypting the list of passwords, thus protecting the passwords against unauthorized, off-line access. Therefore, design and implementation flaws in the key derivation function impact password security significantly. Design and implementation problems in the key derivation function can render the encryption on the password list useless, by for example allowing efficient bruteforce attacks, or - even worse - direct decryption of the stored passwords. In this paper, we analyze the key derivation functions of popular Android Password-Managers with often startling results. With this analysis, we want to raise the awareness of developers of security critical apps for security, and provide an overview about the current state of implementation security of security-critical applications.

The high usability of smartphones and tablets is embraced by consumers as well as the corporate and public sector. However, especially in the non-consumer area the factor security plays a decisive role for the platform-selection process. All of the current companies within the mobile device sector added a wide range of security features to the initially consumer-oriented devices (Apple, Google, Microsoft), or have dealt with security as a core feature from the beginning (RIM, now Blackerry). One of the key security features for protecting data on the device or in device backups are encryption systems, which are available in the majority of current devices. However, even under the assumption that the systems are implemented correctly, there is a wide range of parameters, specific use cases, and weaknesses that need to be considered when deploying mobile devices in security-critical environments. As the second part in a series of papers (the first part was on iOS), this work analyzes the deployment of the Android platform and the usage of its encryption systems within a security-critical context. For this purpose, Android's different encryption systems are assessed and their susceptibility to different attacks is analyzed in detail. Based on these results a workflow is presented, which supports deployment of the Android platform and usage of its encryption systems within security-critical application scenarios.