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This book constitutes the thoroughly refereed post-conference proceedings of the fourth International ICST Conference on Security and Privacy in Mobile Information and Communication Systems (MOBISEC 2012) held in Frankfurt/Main, Germany, in June 2012. The 13 revised full papers were carefully selected from numerous submissions and cover the application layer of security, highlighting the practical importance of security of mobile devices in concrete usages. Contributions to MobiSec 2012 range from treatments on user privacy issues, over mobile application and app security, to mobile identity management, and NFC. With the orientation toward applications, MobiSec is a perfect interface between academia and industry in the field of mobile communications.

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APEFS: An Infrastructure for Permission-based filtering of Android Apps.-A Guidance Model for Architecting Secure Mobile Applications.-Mobile smart card reader using NFC-enabled smartphones.-Claim-based versus network-based identity management: a hybrid approach.-Program Structure-Based Feature Selection for Android Malware Analysis.-Presenting the Brazilian Project TSAM - Security Technologies for Mobile Environments.-Scalable Trust Assessment and Remediation of Wireless Devices.-Verifying the Location of a Mobile Device User.-Context-Aware, Data-Driven Policy Enforcement for Smart Mobile Devices in Business Environments.-Securing Mobile Machine Interactions with Location Histories.-PEPPeR: A querier´s Privacy Enhancing Protocol for PaRticipatory sensing.-Using Extracted Behavioral Features to Improve Privacy for Shared Route Tracks.-Securing Data Privacy on Mobile Devices in Emergency Health Situations.

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