1079 |
|
|
1080 |
|
|
1081 |
\subsection{Anonymity} |
\subsection{Anonymity} |
1082 |
Anonymoys \cite{352607} |
|
1083 |
Anonymoys \cite{293447} |
According to \cite{dingledine00free}, there exists several kinds of anonymity. Author-anonymity is form |
1084 |
|
of anonymity in which no one can link author to a specific document. In publisher-anonymity system, |
1085 |
|
no one is able to link publisher to a specific document. Reader-anonymity means that a specific |
1086 |
|
document cannot be linked to document's readers. This form of anonymity protects the privacy of a |
1087 |
|
system's users. Furthermore, in peer-anonymity means that no peer can be linked to a specific document, i.e. |
1088 |
|
no one is able to determine the peer, where document was originally published. Document-anonymity |
1089 |
|
means that peer doesn't know which data it is currently hosting. Finally, query-anonymity refers is form |
1090 |
|
of document-anonymity; when other peers performs data lookups, peer doesn't know which data it servers |
1091 |
|
to the data lookup originators. As the authors cite, some of forms of anonymity may imply each other and |
1092 |
|
possible issues are one area of future work. |
1093 |
|
|
1094 |
|
With regard to anonymity in Peer-to-Peer systems, there has been done much research work both at network |
1095 |
|
level layer \cite{tarzan:ccs9} and at application level layer \cite{reiter98crowds}, \cite{mixminionurl}. |
1096 |
|
Research on anonymity outside of Peer-to-Peer context have been done also \cite{352607}, \cite{293447}. |
1097 |
|
|
1098 |
|
Obviously, providing several types of anonymity, anonymity often conflicts with other key properties of |
1099 |
|
Peer-to-Peer system. Let's consider anonymity and efficient data lookup. In efficient lookup, we must know |
1100 |
|
the peers responsible to given data in Peer-to-Peer system. Of course, when we know the peers responsible |
1101 |
|
for the data, the anonymity of peer is lost. Fortunately, there are partial solutions to previously |
1102 |
|
mentioned situations, i.e. pseudonym which is a partial form of anonymity. For instance, pseudonym can used for |
1103 |
|
addressing peer-anonymity by providing anonymous-like identifiers to peers (e.g., tightly structured peer |
1104 |
|
identifiers). |
1105 |
|
|
1106 |
|
Anonymity is widely used in those Peer-to-Peer system in which data publication is performed. These include |
1107 |
|
Freenet \cite{clarke00freenet}, Publius \cite{pub00}, Free haven \cite{dingledine00free}, Crowds \cite{reiter98crowds}, |
1108 |
|
Tangler \cite{502002} and upcoming Mnet \cite{mneturl}. Forwarding proxies are used in Freenet, Crowds and |
1109 |
|
Free Haven in order to provide various types of anonymity. Tangler and Publius uses cryptographic |
1110 |
|
sharing methods to split a data into data fragments \cite{Shamir1979a}. Mixmailer networks, such as |
1111 |
|
\cite{mixminionurl}, are commonly used in distributed systems, which are able to provide level |
1112 |
|
of anonymity |
1113 |
|
|
1114 |
|
Even if many existing Peer-to-Peer systems are able to provide some of the types of anonymity, there is no |
1115 |
|
such a system which is able to provide all kinds of anonymity as listed above. Furthermore, the conflicts |
1116 |
|
between anonymity and other Peer-to-Peer system properties requires more research work. |
1117 |
|
|
1118 |
|
|
1119 |
\subsection{Access Control} |
\subsection{Access Control} |
1120 |
\subsection{Fault-tolerance} |
\subsection{Fault-tolerance} |
1123 |
\subsection{Other Security threds} |
\subsection{Other Security threds} |
1124 |
|
|
1125 |
|
|
|
\cite{daswani03openproblems} |
|
|
|
|
|
\cite{sit02securitycons} |
|
1126 |
|
|
1127 |
|
|
1128 |
|
|
|
\cite{ajmani02conchord} |
|
1129 |
|
|
|
\cite{reiter98crowds} |
|
1130 |
|
|
|
\cite{tarzan:ccs9} |
|
1131 |
|
|
|
\cite{pub00} |
|
1132 |
|
|
1133 |
\cite{grahamp2psecurity} |
\cite{grahamp2psecurity} |
1134 |
|
|
1323 |
|
|
1324 |
\section{Summary} |
\section{Summary} |
1325 |
|
|
1326 |
|
\cite{daswani03openproblems} |
1327 |
|
|
1328 |
|
\cite{sit02securitycons} |
1329 |
|
|
1330 |
Main problems in different approaches (own conclusions, based on research efforts): |
Main problems in different approaches (own conclusions, based on research efforts): |
1331 |
1) Decentralized, but structured |
1) Decentralized, but structured |
1332 |
-make routing/system more flexible againts adversial attacks |
-make routing/system more flexible againts adversial attacks |