1.1 --- a/thesis/tex/2-MarketAnalysis.tex	Sat Feb 07 22:51:17 2009 +0100
     1.2 +++ b/thesis/tex/2-MarketAnalysis.tex	Sat Feb 07 23:47:34 2009 +0100
     1.3 @@ -97,7 +97,7 @@
     1.4  
     1.5  \subsubsection*{Communication hardware}
     1.6  
     1.7 -Communication hardware comes from two different roots: On one side, the telephone, now available as mobile phones. This group centers around recorded data and dialog but messages are also supported by the answering machine and \NAME{SMS}. On the other side, mail and its relatives like email, which use computers as main hardware. This part centers around document messages but also supports dialog communication in Instant Messaging and Voice over \NAME{IP}.
     1.8 +Communication hardware comes from two different roots: On one side, the telephone, now available as mobile phones. This group centers around re\-cor\-ded data and dialog but messages are also supported by the answering machine and \NAME{SMS}. On the other side, mail and its relatives like email, which use computers as main hardware. This part centers around document messages but also supports dialog communication in Instant Messaging and Voice over \NAME{IP}.
     1.9  
    1.10  The last years finally brought the two groups together, with \name{smart phones} being the merging hardware element. Smart phones are computers in the size of mobile phones or mobile phones with the capabilities of computers, however one likes to see it. They provide both functions by being telephones \emph{and} computers.
    1.11  \index{smart phone}
    1.12 @@ -165,7 +165,7 @@
    1.13  \hfill\cite{wheeler03}
    1.14  \end{quote}
    1.15  
    1.16 -The amount of spam is huge. Panda Security and Commtouch state in their \name{Email Threats Trend Report} for the second Quarter of 2008: ``Spam levels throughout the second quarter averaged 77\,\%, ranging from a low of 64\,\% to a peak of 94\,\% of all email [...]'' \cite[page 4]{panda:email-threats}. The report sees the main source of spam in bot nets consisting of zombie computers: ``Spam and malware levels remain high for yet another quarter, powered by the brawny yet agile networks of zombie \NAME{IP}s.'' \cite[page 1]{panda:email-threats}. This is supported by IronPort Systems: ``More than 80 percent of spam now comes from a `zombie'---an infected \NAME{PC}, typically in a consumer broadband network, that has been hijacked by spammers.'' \cite{ironport:zombie-computers}. Positive for \MTA{}s is that they are not the main source for spam, but it is only a small delight. Spam is a general weakness of the email system because it is not stoppable.
    1.17 +The amount of spam is huge. Panda Security and Commtouch write in their \name{Email Threats Trend Report} for the second Quarter of 2008: ``Spam levels throughout the second quarter averaged 77\,\%, ranging from a low of 64\,\% to a peak of 94\,\% of all email [...]'' \cite[page 4]{panda:email-threats}. The report sees the main source of spam in bot nets consisting of zombie computers: ``Spam and malware levels remain high for yet another quarter, powered by the brawny yet agile networks of zombie \NAME{IP}s.'' \cite[page 1]{panda:email-threats}. This is supported by IronPort Systems: ``More than 80 percent of spam now comes from a `zombie'---an infected \NAME{PC}, typically in a consumer broadband network, that has been hijacked by spammers.'' \cite{ironport:zombie-computers}. Positive for \MTA{}s is that they are not the main source for spam, but it is only a small delight. Spam is a general weakness of the email system because it is not stoppable.
    1.18  \index{spam!sources of}
    1.19  
    1.20  
    1.21 @@ -265,7 +265,7 @@
    1.22  
    1.23  \MTA{}s are still important in this new email architecture, but in a slightly different way. They do not transfer mail itself anymore, but they transport the notifications about new mail to the destinations. This is a quite similar job as in the \NAME{SMTP} model. The real transfer of the mail, however, can be done in an arbitrary way, for example via \NAME{FTP} or \NAME{SCP}.
    1.24  
    1.25 -A second concept, this one primary to arm against spam, is \person{David~A.\ Wheeler}'s \name{Guarded Email} \cite{wheeler03}. It requires messages to be recognized as Ham (non-spam) to be accepted, otherwise a challenge-response authentication will be initiated.
    1.26 +A second concept, this one primary to arm against spam, is \person{David~A.\ Whee\-ler}'s \name{Guarded Email} \cite{wheeler03}. It requires messages to be recognized as Ham (non-spam) to be accepted, otherwise a challenge-response authentication will be initiated.
    1.27  \index{Guarded Email}
    1.28  
    1.29  \name{Hashcash} by \person{Adam Back}---a third concept---tries to limit spam and denial of service attacks \cite{back02}. It requests payment for email. The costs are computing time for the generation of hash values. Thus sending spam becomes expensive. Further information about \name{Hashcash} can be found on \citeweb{hashcash:homepage}.