This book constitutes the refereed proceedings of the Second International Workshop on Security, IWSEC 2007, held in Nara, Japan, October 29-31, 2007. The 30 revised full papers presented were carefully reviewed and selected from 112 submissions. The papers are organized in topical sections on subjects including Software and Multimedia security, Public-key cryptography, Network security, E-commerce and Voting, Operating systems, and Security and Information management.

Software and Multimedia Security.- A Note on the (Im)possibility of Using Obfuscators to Transform Private-Key Encryption into Public-Key Encryption.- Design Issues of an Isolated Sandbox Used to Analyze Malwares.- Collusion-Resistant Fingerprinting Scheme Based on the CDMA-Technique.- Public-Key Cryptography (1).- Reduction Optimal Trinomials for Efficient Software Implementation of the ? T Pairing.- Experiments on the Linear Algebra Step in the Number Field Sieve.- Batch Pairing Delegation.- Botnet Traffic Detection Techniques by C&C Session Classification Using SVM.- A Global Authentication Scheme for Mobile Ad-Hoc Networks.- An Efficient Pre-authentication Scheme for IEEE 802.11-Based Vehicular Networks.- Intrusion Detection and Identification System Using Data Mining and Forensic Techniques.- Run-Time Randomization to Mitigate Tampering.- Privacy-Preserving Eigentaste-Based Collaborative Filtering.- Secure and Private Incentive-Based Advertisement Dissemination in Mobile Ad Hoc Networks.- Verifiable Internet Voting Solving Secure Platform Problem.- Enforcement of Integrated Security Policy in Trusted Operating Systems.- Salvia: A Privacy-Aware Operating System for Prevention of Data Leakage.- InfoCage: A Development and Evaluation of Confidential File Lifetime Monitoring Technology by Analyzing Events from File Systems and GUIs.- Public-Key Cryptography (2).- Accredited Symmetrically Private Information Retrieval.- Generic Certificateless Encryption in the Standard Model.- On Security Models and Compilers for Group Key Exchange Protocols.- Processing Multi-parameter Attacktrees with Estimated Parameter Values.- Practical Security Analysis of E-Voting Systems.- Fine-Grained Sticky Provenance Architecture for Office Documents.- Secure Anonymous Communications withPractical Anonymity Revocation Scheme.- GAS: Overloading a File Sharing Network as an Anonymizing System.- A Composite Privacy Protection Model.- Nominative Signature from Ring Signature.- Anonymous Authentication Protocols with Credit-Based Chargeability and Fair Privacy for Mobile Communications.- How to Find Many Collisions of 3-Pass HAVAL.- A Secure Threshold Anonymous Password-Authenticated Key Exchange Protocol.