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

[Hermanni Hyytiälä]

CVSROOT:        /cvsroot/gzz
Module name:    gzz
Changes by:     Hermanni Hyytiälä <address@hidden>      03/03/06 05:44:06

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

Log message:
        done

CVSWeb URLs:
http://savannah.gnu.org/cgi-bin/viewcvs/gzz/gzz/Documentation/misc/hemppah-progradu/masterthesis.tex.diff?tr1=1.121&tr2=1.122&r1=text&r2=text

Patches:
Index: gzz/Documentation/misc/hemppah-progradu/masterthesis.tex
diff -u gzz/Documentation/misc/hemppah-progradu/masterthesis.tex:1.121 
gzz/Documentation/misc/hemppah-progradu/masterthesis.tex:1.122
--- gzz/Documentation/misc/hemppah-progradu/masterthesis.tex:1.121      Thu Mar 
 6 05:08:37 2003
+++ gzz/Documentation/misc/hemppah-progradu/masterthesis.tex    Thu Mar  6 
05:44:05 2003
@@ -21,7 +21,7 @@
 
 \translatedtitle{Fenfire vertaisverkko ymp?rist?ss?}
 
-\author{Hermanni Hyyti?l?}
+\author{Hermanni Hyytiälä}
 
 \linja{Software Engineering}
 
@@ -29,13 +29,13 @@
 
 \keywords{Peer-to-Peer, P2P, security, Distributed systems, Hypermedia systems}
 
-\avainsanat{Vertaisverkot, P2P, tietoturva, hajautetut j?rjestelm?t, 
hypermedia-j?rjestelm?t}
+\avainsanat{Vertaisverkot, P2P, tietoturva, hajautetut järjestelmät, 
hypermedia-järjestelmät}
 
 \contactinformation{\\
-Hermanni Hyyti?l?\\
+Hermanni Hyytiälä\\
 Huhtalammentie 5 as. 17\\
-40640 JYV?SKYL?\\
-s?hk?posti: address@hidden
+40640 Jyväskylä\\
+sähköposti: address@hidden
 
 
 \abstract{
@@ -51,16 +51,16 @@
 related data from Peer-to-Peer network.
 }
 \tiivistelma{
-T?ss? opinn?ytety?ss? arvioimme olemassaolevia vertaisverkkoja, protokollia ja
+Tässä opinnäytetyössä arvioimme olemassaolevia vertaisverkkoja, protokollia ja
 niiden erityisominaisuuksia. Teemme yhteenvedon olemassa olevista ongelmista
 vertaisverkoissa ja jaamme ongelmat kolmeen alakategoriaan. Havaitsemme, ett?
 on olemassa useita ongelmia, joihin ei ole ratkaisua lainkaan, tai on ehdotelma
-ongelman ratkaisemiseksi, mik? k?yt?nn?ss? on kuitenkin mahdotonta toteuttaa.
+ongelman ratkaisemiseksi, mikä käytönnössä on kuitenkin mahdotonta toteuttaa.
 
-T?m?n j?lkeen annamme yleiskuvan Fenfire-j?rjestelm?st?.
-Arvioimme olemassaolevia vertaisverkkoarkkitehtuureja-- l?yh?sti ja tiukasti
-rakennettuja p??llysverkkoja-- Fenfiren vaatimusten valossa. Lopuksi ehdotamme
-yksin-kertaisia algoritmeja, joiden avulla voidaan tehokkaasti l?yt??
+Tämän jälkeen annamme yleiskuvan Fenfire-järjestelmästä.
+Arvioimme olemassaolevia vertaisverkkoarkkitehtuureja-- löyhästi ja tiukasti
+rakennettuja päällysverkkoja-- Fenfiren vaatimusten valossa. Lopuksi ehdotamme
+yksin-kertaisia algoritmeja, joiden avulla voidaan tehokkaasti löytää
 vertaisverkosta Fenfire:n kannalta olennaista tietoa
 }
 
@@ -509,7 +509,7 @@
 \exists s \in S$, $ip = map(identifier(s)) \wedge (provider(s) = p)$\}., 
 which means that resources which peer provides into the system are not kept 
locally.
 Every $p$ has neighbor(s), named as $neighbor$, which are $P$ = \{$p \in P: 
\exists neighbor$, 
-where $difference(p,p_neighbor)= ''close''$, where ?$''close''$ is small 
difference $d$ in $(IS,d)$\}.
+where $difference(p,p_neighbor)= ''close''$, where $''close''$ is small 
difference $d$ in $(IS,d)$\}.
 
 
 \section{Summary}
@@ -925,12 +925,13 @@
 al \cite{296824}. 
 
 Spam generating attack is another known attack model againts Peer-to-Peer 
system. In Spam
-attack, hostile or faulty peer may produce false information of the data. 
Possible solution againts this attack
-is that peer should not trust to single entity. Instead peer should get 
information from multiple entities and trust 
-on majority's opinion. This methods requires more messages to be sent to 
network increasing the load of system. 
-However, if Spam attack is combined with Sybil attack, obviously previously 
mentioned solution doesn't work. 
-Again, more research is required to solve this attack model reliability. Naor 
et al. \cite{naor03simpledht} has 
-proposed a partial solution againts Spam attack with \emph{faulty} peers (not 
hostile).
+attack, hostile or faulty peer may produce false information of the data, or 
refuses/is not able to reply to requests. 
+Possible solution againts this attack is that peer should not trust to single 
entity. Instead peer should get 
+information from multiple entities and trust on majority's opinion. This 
methods requires more messages to be 
+sent to network increasing the load of system. However, if Spam attack is 
combined with Sybil attack, obviously 
+previously mentioned solution doesn't work. Again, more research is required 
to solve this attack model 
+reliability. Naor et al. \cite{naor03simpledht} has proposed a partial 
solution againts Spam attack with 
+\emph{faulty} peers (not hostile).
 
 Traditional overload of targeted peers is best known form of distrubuted 
Denial of Service attack (DDoS). For example, 
 hostile entity can attempt to burden targetted peers with garbage packets. As 
a implication, peers may act
@@ -1647,7 +1648,7 @@
 
 \chapter{Fenfire hypermedia system}
 
-In this chaper we give an overview of Fenfire system and its objectives. We 
also 
+In this chaper we give an overview of Fenfire system. We also 
 describe briefly xanalogical model. At the end of this chapter we study Storm, 
 Fenfire's software module, which is an essential part of Fenfire's 
Peer-to-Peer 
 functionality. 
@@ -1686,7 +1687,7 @@
 scenario: ''the character 'D' typed by Janne Kujala on 10/8/97 8:37:18''. In 
this
 example, when character 'D' is is first typed in, xanalogical storage model
 acquires a permanent identifier for that character and retains it when 
character
-is copied to different document. Thus, identifier distinguishes chararacter 
from 
+is copied to different document. Thus, the identifier distinguishes 
chararacter from 
 all similar characters typed in independently\footnote{Xanalogical storage 
model
 is not limited to text. It can support arbitrary data, e.g., pixels of picture 
or 
 frames of video.}. The connectivity in xanalogical storage model between data 
content 
@@ -1886,8 +1887,8 @@
 locating data efficiently in the Peer-to-Peer overlay. There are two main
 reasons for this. First, Kamdelia's XOR-based distance function is superior
 over the distance functions of other systems. Second, there are already some 
-real-life systems (e.g., \cite{overneturl}, \cite{edonkey2kurl}, 
\cite{kashmirurl}), 
-which means that Kademlia's algorithm is simple and easy to implement.
+real-life systems (e.g., \cite{overneturl}, \cite{edonkey2kurl}, 
\cite{kashmirurl},
+\cite{kato02gisp}), which means that Kademlia's algorithm is simple and easy 
to implement.
 
 In top of Kademlia, we propose the usage of Sloppy hashing 
\cite{sloppy:iptps03} which
 optimized for DOLR abstraction of tightly structured overlays. With Sloppy 
hashing, 
@@ -1994,57 +1995,27 @@
 \end{figure}
 
 
+\subsection{Problems}
 
-\chapter{Open issues and future work}
+Perhaps the most biggest issue in Peer-to-Peer systems is non-maturity of
+secure techologies. For instance online entities cannot be identified 
+safely (e.g., the Sybil attack \cite{douceur02sybil}). For Fenfire, one
+security related problem occurs when user wants to perform global data lookup 
with a given
+pointer random string; how user is able to verify the correctness
+of the search results, and how do we know which one is the 
+correct Storm scroll block ? Spam attack is variation of previously
+mentioned problem; data lookup is performed by a user, but there is no reply
+from the system. How do we are able to know if this was a spam attack, or the
+data really no exist in the system ? Another problem related to Fenfire's 
+security is that if a user downloads data from the network to local computer 
+and after network disconnetcion, user wants to verify \emph{offline} the 
+authenticity of data. Obviously, optimal solution to all security issues would 
+be that digital signatures are included to every message sent in the system. 
+However, these problems are not only limited to Fenfire, it concerns all 
+Peer-to-Peer based computer systems. We believe these problem is solved in a 
+near future as very intesive research is carried out in Peer-to-Peer field.
 
-One of the most important issues in Peer-to-Peer networks is the fact that
-online entities cannot be identified and verifyied safely. For our purposes
-this is a problem when user wants to perform global search with a given
-urn-5 random string. For instance, how user is able to verify the correctness
-of the search results ? Which one is the correct scroll block ? Furthermore,
-if user downloads data to local computer and wants to verify \emph{offline}
-that data really came from the entity which it was supposed to. These problems
-are not only limited to our Storm design, it concerns all Peer-to-Peer
-based computer systems. However, we believe this problem is solved in a near 
-future as Peer-to-Peer networks will come more and more important in 
-computing world.
-
--benefis over p2p filesharing programs
-
--'get me block XYZ'
--there is no reply, how do we are able to know if this was a spam attack, or 
the
-data really no exist in the system ?
-
--search engine ?
-
--digital signature on messages (no spam attacks) ?
--lack of working PKI architecture
-
-Our future work includes support for searching transclusions and xanalogical
-links in a Peer-to-Peer network. Specifically, we want to find transclusions
-or xanalogical links in a global scale. Preliminary analysis have showed
-that these questions are rather different than locating scroll or pointer
-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 
-Kademlia \cite{maymounkov02kademlia}, Koorde \cite{kaashoek03koorde} and
-Chord \cite{stoica01chord}. One possibility for future work is to 
-implement multisource downloading, which would creatly improve the 
-performance of fetching large amounts of scroll blocks from the network.
-Additionally, we will likely use both DHT and DOLR methods when performing
-data lookups in the network. DOLR is used under normal condition and DHT
-when inviduals wants mirror their data to other peers. Again, future work
-is required how to implement this sensibly way.
-
-
-\cite{gribble01p2pdatabase}
-
-\chapter{Conclusions}
+\chapter{Conclusions and future work}
 
 In this thesis, we have reviewed existing Peer-to-Peer approaches, algorithms 
and
 their properties. Currently, two main Peer-to-Peer overlay approaches
@@ -2074,12 +2045,22 @@
 of locality in tightly structured overlays. Finally, we believe that issues 
 related to tightly structured overlays are solved in near future, because of
 wide and intensive co-operation among research groups.
- 
-
 
-\bibliographystyle{gradu}
-\bibliography{progradu}
+Our future work includes support for searching transclusions and xanalogical
+links in a Peer-to-Peer network. Specifically, we want to find transclusions
+or xanalogical links in a global scale. Preliminary analysis have showed
+that these questions are rather different than locating scroll or pointer
+blocks \emph{directly} from the network. Techiques used in distributed 
+database systems may prove to be useful. Some fundamental results
+regarding Peer-to-Peer and database systems has already been
+presented \cite{gribble01p2pdatabase}. 
 
+As security techologies comes more mature, we wish to apply these 
+techologies with Fenfire, if applicable.
 
+In the following months, we will implement a Fenfire Peer-to-Peer 
+prototype. 
 
+\bibliographystyle{gradu}
+\bibliography{progradu}
 \end{document}