Transcript ethics and privacy

LIS508 almost last lecture:
Privacy and Ethics
Thomas Krichel
2003-12-09
The unethical network
• There are a lot of ethical issues arising in
computer networks!
• Here we list a few.
Offensive Speech
• WWW and other network installations are
full of speech that offends some
– views on religion and politics
– sexually explicit material
– spam
• Are Internet Service Providers (ISPs)
reliable for contents?
• Are they allowed to restrict contents?
Government snooping
• FBI has installed a system at many ISPs to
snoop email for any interesting contents.
• Originally called carnivore, now DCS1000.
• But fourth amendment prohibit searches without
a search warrant.
• At the world summit for the information society,
developing countries have pushed for UN
control of the Internet.
Private snooping
• Web providers have cookies installed to
recognize users of the some machine.
• If this is a home machine, behavior of a
user may be quite traceable.
• But, of course, it can be used to provide
convenient features that overcome the
stateless nature of http.
Illegal copying
• Some copyright holders view the Internet
as a giant copying machine.
• They may be right when it comes to file
sharing.
• File sharing operates on peer-to-peer
networks exchanging information.
Peer-to-Peer (P2P)
• Most Internet services are based on a
client/server architecture.
• In a P2P architecture, users run clients
that also run as servers, called "servents".
• But we can stick to client/server way of
terminology
– You act as a client when I want something
– You act as a server when you give something
Napster
• Napster is sometimes referred to as a p2p
network. This is not quite true.
• Napster ran a central server. You
connected to that server and announced
what files you had to share.
• Every search was conducted on the
dataset assembled at the central server.
• Connections to download files where done
between peer machines only!
end of Napster
• Napster argued since it was only involved in
collecting the information about files available, it
was legal.
• Napster never shared any illegal file.
• The courts thought otherwise.
• It was shut down.
• Napster network died without a central machine.
• To enable true piracy, we need a truly distributed
system.
gnutella protocol
• This protocol underlies much of the current
file-sharing activity on the Internet.
• It is based on TCP/IP and http!
• A file sharing network (fsn) is a bunch of
machines that exchange files using
gnutella.
• To connect to a gnutella network, you
need the IP address of one single machine
that is already part of the network.
connection to a fns
• Once you establish connection to the first
servent, you announce your presence.
• The first servent will pass on that message
to all the servents that it is connected to,
and so on.
• These servents all reply with data about
themselves
– how many files it is sharing
– how many kilo bytes the files take up
• This already adds up to a lot of traffic!
time to live
• Every gnutella message has a time to live
(ttl). It is decremented every time it passes
at a servent.
• The TTL is usually quite small. It can be
arbitrarily reduced by servents.
• The number of servents that the packet
has already been rooted to is also noted.
detail on the message
• MessageID
• FunctionID
16 bytes
1 byte
ID
function of packet
– search
– connection announcement (initialization), etc.
• RemainingTTL 1 byte
TTL left to this packet
• HopsTaken
1 byte
number of servents this
packet has already been routed through
• DataLength
4 bytes
size of the remaining
data in the packet
• (no need to remember for quiz)
example scenario
• Alice starts a servent. Knows Charlie's IP and
send him an init packet.
• Charlie gets it and routes it to Bob and Eve.
They pass it on further and so on, until TTL is
reached.
• Charlie sends his file data to Alice.
• Charlie gets responses from Bob and Eve,
sends it to Alice…
• Everyone only knows about the servents that
they are connected to.
searches
• When you do a search, it is passed on
from servent to servent through the fsn.
• Servents have their own rule how to
repond to queries.
– If you search for '.mp3'
• a servent may only look for a file '.mp3'
• a servent may look for all files ending with .mp3
– Servents may respond with a truncated
results set.
• Searches are public, most fsn software
has a search monitor.
downloading
• to establish downloads the servents use
http.
• this is a well-established protocol with a
good code base.
• Thus everyone who is connected to a file
sharing network run a web server!
ease to infringe
• Clearly all the traffic on a fsn, with current
technology, can be observed.
• But the infringement is so massive that it
appears difficult to clamp down on.
• The easy to infringe is technological.
• RIAA have sued. They reach the tippy top
of the iceberg, with the hope to dissuade.
copyright holders are scared
• ISPs can keep track who has what IP at a
given moment.
• Some block the ports that are used for file
sharing.
• Copyright holders have demanded these
lists.
• This is a violation of customer privacy.
Freenet
• This is as different file sharing system that
is still under development. It aims:
– To allow people to distribute material
anonymously.
– To allow people to retrieve material
anonymously.
– To make the removal of material almost
insuperably difficult.
– To operate without central control.
• Ethics are more political.
operation of freenet
• Searches are only passed to one other
servent, which pass it on. After no positive
response from that chain, another servent
is tried.
• But the entire document sought is passed
along, unless it is too large
• Servents keep caches of popular
documents until no one asks for it for a
long time.
• popular documents frequent and close to
users.
searching on freenet
• You basically can not search on freenet.
• Each document has an identifier. The
identifier and the document can not be
changed.
• This will make it difficult to use it on its
own as a device for people to exchange
copyrighted material.
http://openlib.org/home/krichel
Thank you for your attention!