Towards fault-tolerant and secure on-line services

摘要: Integrating fault tolerance and security is crucial for building trustworthy on-line services. Such integration studied in this dissertation through the design implementation of COCA (Cornell On-line Certification Authority), a fault-tolerant secure certification authority. maintains service private key to sign responses it sends clients, achieves availability using replicated servers that employ threshold cryptography store shares key. Periodic share refreshing, coupled with periodic recovery server states, defends against so-called mobile adversaries which move from one another. designed weak system model: no assumptions are made about speed or message delay, communications assumed links intermittent. The result reduced vulnerability attacks because, by their nature, weaker more difficult invalidate. further employs an array defense mechanisms specific denial attacks. runs both on local area network Internet. Performance measurements under simulated demonstrate effectiveness COCA's defenses.