Valet Services: Improving Hidden Servers with a Personal Touch

Location hidden services have received increasing attention as a means to resist censorship and protect the identity of service operators. Research and vulnerability analysis to date has mainly focused on how to locate the hidden service. But while the hiding techniques have improved, almost no progress has been made in increasing the resistance against DoS attacks directly or indirectly on hidden services. In this paper we suggest improvements that should be easy to adopt within the existing hidden service design, improvements that will both reduce vulnerability to DoS attacks and add QoS as a service option. In addition we show how to hide not just the location but the existence of the hidden service from everyone but the users knowing its service address. Not even the public directory servers will know how a private hidden service can be contacted, or know it exists.