and Background.- Authorizations.- An Architectural Model for Secure Authorizations.- Traditional Security Objectives.- Personal Data Protection Objectives.- The Challenge: Technical Enforcement of Multilateral Security.- Pseudonyms - A Technical Point of View.- An Architectural Model for Pseudonymous and Secure Authorizations.- Comparing Architectures.- Audit Data Pseudonymization.- Set-based Approach.- Requirements, Assumptions and Trust Model.- Modeling Conditions for Technical Purpose Binding of Controlled Pseudonym Disclosure.- Cryptographic Enforcement of Disclosure Conditions.- The Mismatch Problem.- Operational Pseudonymization and Pseudonym Disclosure.- Extensions.- Application to Unix Audit Data.- Unix Audit Data.- Syslog.- Instantiating the Set-based Approach for Syslog-style Audit Data.- Implementation: Pseudo/CoRe.- Evaluation.- APES: Anonymity and Privacy in Electronic Services.- Evaluating the Design Using Basic Building Blocks for Anonymity.- Evaluating the Performance of the Implementation.- Refinement of Misuse Scenario Models.- Motivating Model Refinements.- Models of Misuse Scenarios.- Pseudonymization Based on Serial Signature-Nets.- Pseudonym Linkability.- Pseudonym Disclosure.