
diff -r 4a0bff167159 -r 6d13b8da019e handouts/ho08.tex
--- a/handouts/ho08.tex	Fri Nov 06 08:51:53 2015 +0000
+++ b/handouts/ho08.tex	Tue Nov 10 22:28:03 2015 +0000
@@ -2,9 +2,11 @@
 \usepackage{../style}
 \usepackage{../graphics}
 \usepackage{../langs}
+\usepackage{../data}
+
 
 \begin{document}
-\fnote{\copyright{} Christian Urban, 2014}
+\fnote{\copyright{} Christian Urban, 2014, 2015}
 
 \section*{Handout 8 (Bitcoins)}
 
@@ -397,8 +399,7 @@
 controlled by changing the target according to the available
 computational power available. I think the adjustment of the
 hardness of the problems is done every 2060 blocks
-(appr.~every two weeks). I am not sure whether this is an
-automatic process. The aim of the adjustment is that on
+(appr.~every two weeks). The aim of the adjustment is that on
 average the Bitcoin network will most likely solve a puzzle
 within 10 Minutes. 
 
@@ -530,19 +531,21 @@
 group.
 
 Connected with the 6-confirmation rule is an interesting
-phenomenon. On average, it would take several years for a typical
-computer to solve a proof-of-work puzzle, so an individual’s chance of
-ever solving one before the rest of the world, which typically takes
-only 10 minutes, is negligibly low. Therefore many people join groups
-called \emph{mining pools} that collectively work to solve blocks, and
-distribute rewards based on work contributed. These mining pools act
-somewhat like lottery pools among co-workers, except that some of
-these pools are quite large, and comprise more than 20\% of all the
-computers in the network. It is said that BTC, a large mining pool,
-has limited its number of members in order to not solve more than 6
-blocks in a row. Otherwise this would undermine the trust in Bitcoins,
-which is also not in the interest of BTC, I guess.  Some statistics on
-mining pools can be seen at
+phenomenon. On average, it would take several years for a
+typical computer to solve a proof-of-work puzzle, so an
+individual’s chance of ever solving one before the rest of the
+world, which typically takes only 10 minutes, is negligibly
+low. Therefore many people join groups called \emph{mining
+pools} that collectively work to solve blocks, and distribute
+rewards based on work contributed. These mining pools act
+somewhat like lottery pools among co-workers, except that some
+of these pools are quite large, and comprise more than 20\% of
+all the computers in the network. It is said that BTCC, a
+large mining pool, has limited its number of members in order
+to not solve more than 6 blocks in a row. Otherwise this would
+undermine the trust in Bitcoins, which is also not in the
+interest of BTCC, I guess. Some statistics on mining pools can
+be seen at
 
 \begin{center}
 \url{https://blockchain.info/pools}
@@ -550,11 +553,12 @@
 
 \subsubsection*{Bitcoins for Real}
 
-Let us now turn to the nitty gritty details. As a participant in the
-Bitcoin networ you need to generate and store a public-private key
-pair. The public key you need to advertise in order to receive
-payments (transactions). The private key needs to be securely stored.
-For this there seem to be three possibilities
+Let us now turn to the nitty gritty details. As a participant
+in the Bitcoin network you need to generate and store a
+public-private key pair. The public key you need to advertise
+in order to receive payments (transactions). The private key
+needs to be securely stored. For this there seem to be three
+possibilities
 
 \begin{itemize}
 \item an electronic wallet on your computer
@@ -562,13 +566,14 @@
 \item paper-based
 \end{itemize}
 
-\noindent The first two options of course offer convenience for making
-and receiving transactions. But given the nature of the private keys
-and how much security relies on them (recall if somebody gets hold of
-it, your Bitcoins are quickly lost forever) I would opt for the third
-option for anything except for trivial amounts of Bitcoins. As we have
-seen earlier in the course, securing a computer system that it can
-withstand a breakin is still very much an unsolved problem.
+\noindent The first two options of course offer convenience
+for making and receiving transactions. But given the nature of
+the private keys and how much security relies on them (recall
+if somebody gets hold of it, your Bitcoins are quickly lost
+forever) I would opt for the third option for anything except
+for trivial amounts of Bitcoins. As we have seen earlier in
+the course, securing a computer system that it can withstand a
+targeted breakin is still very much an unsolved problem.
 
 An interesting fact with Bitcoin keys is that there is no
 check for duplicate addresses. This means when generating a
@@ -650,7 +655,7 @@
 selling computing power that you can use to run your web site,
 for example. It is \emph{elastic} in the sense that if you
 have a lot of visitors, you pay a lot, if you have only a few,
-then it is cheap. In order to bill you they, you need to set
+then it is cheap. In order to bill you, you need to set
 up an account with Amazon and receive some secret keys in
 order to authenticate you. The clever (but also dangerous) bit
 is that you upload the code of your web site to GitHub and




