Authorization Architectures for Privacy-Respecting Surveillance -- Privacy-Preserving Revocation Checking with Modified CRLs -- E-Passports as a Means Towards the First World-Wide Public Key Infrastructure -- An Interdomain PKI Model Based on Trust Lists -- One-More Extension of Paillier Inversion Problem and Concurrent Secure Identification -- An Efficient Signcryption Scheme with Key Privacy -- Direct Chosen-Ciphertext Secure Hierarchical ID-Based Encryption Schemes -- Certificate-Based Signature: Security Model and Efficient Construction -- Time Capsule Signature: Efficient and Provably Secure Constructions -- A New Variant for an Attack Against RSA Signature Verification Using Parameter Field -- AutoPKI: A PKI Resources Discovery System -- Bootstrapping a Global SSO from Network Access Control Mechanisms -- Anonymous k-Show Credentials -- On Partial Anonymity in Secret Sharing -- Anonymous Identification and Designated-Verifiers Signatures from Insecure Batch Verification -- OpenHSM: An Open Key Life Cycle Protocol for Public Key Infrastructure’s Hardware Security Modules -- Two Worlds, One Smart Card: An Integrated Solution for Physical Access and Logical Security Using PKI on a Single Smart Card -- On the Robustness of Applications Based on the SSL and TLS Security Protocols -- Using WebDAV for Improved Certificate Revocation and Publication -- Reducing the Computational Cost of Certification Path Validation in Mobile Payment -- Security-by-Contract: Toward a Semantics for Digital Signatures on Mobile Code -- Applicability of Public Key Infrastructures in Wireless Sensor Networks -- Spatial-Temporal Certification Framework and Extension of X.509 Attribute Certificate Framework and SAML Standard to Support Spatial-Temporal Certificates -- Electronic Payment Scheme Using Identity-Based Cryptography -- Undeniable Mobile Billing Schemes -- Universally Composable Signcryption -- Chord-PKI: Embedding a Public Key Infrastructure into the Chord Overlay Network -- Privacy Protection in Location-Based Services Through a Public-Key Privacy Homomorphism -- A Critical View on RFC 3647.

This book constitutes the refereed proceedings of the 4th European Public Key Infrastructure Workshop: Theory and Practice, EuroPKI 2007, held in Palma de Mallorca, Spain in June 2007. The 21 revised full papers and 8 short papers presented were carefully reviewed and selected from 77 submissions. The papers address all current issues in PKI, ranging from theoretical and foundational topics to applications and regulatory issues in various contexts.