The Domain Name System (DNS) does not provide query privacy. Query obfuscation schemes have been proposed to overcome this limitation, but, so far, they have not been evaluated in a realistic setting. In this paper we evaluate the security of a random set range query scheme in a real-world web surfing scenario. We demonstrate that the scheme does not sufficiently obfuscate characteristic query patterns, which can be used by an adversary to determine the visited websites. We also illustrate how to thwart the attack and discuss practical challenges. Our results suggest that previously published evaluations of range queries may give a false sense of the attainable security, because they do not account for any interdependencies between queries.
In a society preoccupied with gradual erosion of electronic privacy, loss of privacy in current DNS queries is an important issue worth considering. From the definition, the privacy problem is to prove that none of the private data can be inferred from the information which is made public. The privacy disclosure problem in DNS Query was well analyzed by from MUE 2007. In this paper, we first analyze the "Range Query " from that paper, then by results of that scheme and another well-known client- to-server privacy-preserving query scheme: Two- DBServer Private Information Retrieval theory, we propose a new privacy-preserving DNS Query scheme, which was proved to achieve higher efficiency and theoretic privacy. When a DNS (domain name system) client needs to look up a name, it queries DNS servers to resolve the name on the Internet. The query information from the client was passed through one or more DNS servers. While useful, in the whole query transmission, we say it can leak potentially sensitive information: what a client wants to connect to, or what the client is always paying attention to. From the definition, the privacy problem is to prove that none of the private data can be inferred from the information which is made public. We first analyzed the complete DNS query process now in use; then, from each step of the DNS query process, we discussed the privacy disclosure problem in each step of the query: client side, query transmission process and DNS server side. Finally, we proposed a simple and flexible privacy-preserving query scheme "range query", which could maximally decrease privacy disclosure in the whole DNS query process. And we also discuss efficiency and implementation on the range query. We describe schemes that enable a user to access k replicated copies of a database (k spl ges 2) and privately retrieve information stored in the database. This means that each individual database gets no information on the identity of the item retrieved by the user. For a single database, achieving this type of privacy requires communicating the whole database, or n bits (where n is the number of bits in the database). Our schemes use the replication to gain substantial saving. In particular, we have: A two database scheme with communication complexity of O(n sup 1 3 ). A scheme for a constant number, k, of databases with communication complexity O(n sup 1 k ). A scheme for 1 3 log sub 2 n databases with polylogarithmic (in n) communication complexity.