[Gzz-commits] gzz/Documentation/misc/hemppah-progradu mastert...

[Hermanni Hyytiälä]

CVSROOT:        /cvsroot/gzz
Module name:    gzz
Changes by:     Hermanni Hyytiälä <address@hidden>      03/03/03 03:47:01

Modified files:
        Documentation/misc/hemppah-progradu: masterthesis.tex 

Log message:
        Started open problems

CVSWeb URLs:
http://savannah.gnu.org/cgi-bin/viewcvs/gzz/gzz/Documentation/misc/hemppah-progradu/masterthesis.tex.diff?tr1=1.99&tr2=1.100&r1=text&r2=text

Patches:
Index: gzz/Documentation/misc/hemppah-progradu/masterthesis.tex
diff -u gzz/Documentation/misc/hemppah-progradu/masterthesis.tex:1.99 
gzz/Documentation/misc/hemppah-progradu/masterthesis.tex:1.100
--- gzz/Documentation/misc/hemppah-progradu/masterthesis.tex:1.99       Fri Feb 
28 09:42:46 2003
+++ gzz/Documentation/misc/hemppah-progradu/masterthesis.tex    Mon Mar  3 
03:47:01 2003
@@ -285,7 +285,7 @@
 structured Peer-to-Peer systems have adopted this method with some 
modifications
 \cite{gnutella2url}, \cite{shareazaurl}, \cite{fasttrackurl}, 
\cite{morpheusurl}, 
 \cite{kazaaurl}, \cite{jxtaurl}, \cite{jxtaoverview}, 
\cite{botros01jxtasearch},
-\cite{ganesan02yappers}, \cite{kato02gisp}.
+\cite{ganesan02yappers}.
 Figures \ref{fig:gnutella_overlay_supernodes} and 
\ref{fig:gnutella_overlay_cluster}
 illustrated two possible variations of power-law overlay networks. All the 
systems
 share the property of that high degree peers maintain index of all other peers 
@@ -972,10 +972,67 @@
 
 \chapter{Open Problems in Peer-to-Peer}
 
+In this chapter, we discuss open problems in Peer-to-Peer domain. We describe
+open problems and their proposed solutions. Then, we list all issues in
+tables; we list description of the problem, solution and comments on that
+specific open problem. Note that open problems list considered here is not 
meant
+to be an exhaustive survey of \emph{all} open problems in Peer-to-Peer domain; 
+we focus our attention to security, scalability and performance related issues
+only.
+
+\section{Overview}
+
+Partly due to the non-maturity of modern Peer-to-Peer technology, it has 
several
+open problems to be solved. Main open problems are related to performance, 
scalability
+and security. More important, many techniques developed for traditional 
distributed
+systems may no longer apply with Peer-to-Peer systems. Therefore, new 
solutions are 
+needed to make Peer-to-Peer systems more secure and efficient.
+
+Both loosely structured and tightly structured approach have their own main 
problems. 
+Since Napster \cite{napsterurl} and Gnutella \cite{gnutellaurl} was first time 
introduced 
+to public, researchers' main concern has been scalability problem of loosely 
structured 
+approach. However, people often misunderstand the scalability problem of 
loosely structured 
+approach; loosely structured approache's \emph{network} is scalable, but the 
\emph{query model} is not 
+scalable. Tightly structured approach's main concern is to make overlay's data 
lookup 
+routing more flexible againts hostile attacks. Another key problems in tightly 
structured 
+approach are the lack of keyword searches and support for heterogeneous peers.
+
+To make Peer-to-Peer systems even more popular (e.g., in industry), 
Peer-to-Peer domain
+needs better infrastructures to deal with security issues. There has been done 
some
+research regarding anonymity, access control, data availability and data 
integrity. However,
+more research is needed specifically with redundancy, robustness and entity 
identification.
+
+
 \section{Security problems in Peer-to-Peer}
 
+In this section we discuss security problems related to Peer-to-Peer domain.
+
 \subsection{Attacks}
 
+There are five well known attack models againts Peer-to-Peer systems: Sybil 
attack \cite{douceur02sybil},
+Fail-stop attack, Spam attack \cite{naor03simpledht}, Byzantine problem 
\cite{357176} and \cite{296824}, and
+general Distrubuted Denial of Service attack. 
+
+In Sybil attack model, hostile entity presents multpile 
+entities. Therefore, one hostile entity can control a large fraction of the 
Peer-to-Peer system. The best
+possible solution to Sybil attack would be that system could \emph{distinct} 
entities reliably. Unfortunately,
+currently there no realizable techiques for this task. Partial solutions for 
Sybil is attack is to replicate
+and fragment data randomly among several participating peer. However, both 
suggestions assume that two different 
+remote entities are actually different; Sybil attacks are still possible and 
therefore, would need centralized 
+authority for reliable authentication. As author arques in 
\cite{douceur02sybil}, without centralized authority, 
+Sybil attacks are always possible in Peer-to-Peer system except under extreme 
and unrealistic assumptions of 
+resource parity and coordination among entities.
+ 
+
+
+1) Sybil attack \cite{douceur02sybil} 
+2) Fail-stop
+3) Spam generating model \cite{naor03simpledht}
+4) Byzantine problem \cite{357176}, p2p domain \cite{296824}
+5) General DDoS
+
+
+
 1) Sybil attack \cite{douceur02sybil} 
 2) Fail-stop
 3) Spam generating model \cite{naor03simpledht}
@@ -1002,14 +1059,6 @@
 c) Are there lower bounds for average degree of nodes, query path length etc. 
for a network that is
 fault tolerant to linear number of adversial faults ?
 
-Solutions for Sybil Attack: 
-1) data replication among several peers
-2) data fragmentation among several peer
-
-BUT: 
--in either case, both approaches assumes that two different remote entities 
are actually different; sybil attacks are still possible --> need for 
centralized authority
--in p2p environment, trusting to collective assurance of multiple signatories 
(like PGP) is not safe/undermines the authenticity of system (because of sybil 
attacks)
--\cite{douceur02sybil} argues that Sybil attacks are always possible except 
under extreme and unrealistic assumptions of resource parity and coordination 
among entities
 
 
 \subsection{Data authenticity and integrity}
@@ -2124,6 +2173,8 @@
 blocks \emph{directly} from the network. Techiques used in distributed 
 database systems may prove to be useful. However, more research is needed
 in this area. 
+
+\cite{kato02gisp}
 
 In the following months, we will implement a working Storm Peer-to-Peer 
 prototype. Potential candidates for tightly structured overlays are