This book constitutes the proceedings of the 15th European Symposium on Computer Security held in Athens, Greece in September 2010. The 42 papers included in the book were carefully reviewed and selected from 201 papers. The articles are organized in topical sections on RFID and Privacy, Software Security, Cryptographic Protocols, Traffic Analysis, End-User Security, Formal Analysis, E-voting and Broadcast, Authentication, Access Control, Authorization and Attestation, Anonymity and Unlinkability, Network Security and Economics, as well as Secure Update, DOS and Intrustion Detection.