678 \noindent The only thing I can add is that with Bitcoins we

   678 \noindent The only thing I can add to this is that with the Bitcoin

   679 will in the future have even more fun hearing confessions from

   679 blockchain we will in the future have even more pleasure hearing

   680 famous or not-so famous people like the infamous

   680 confessions from reputable or not-so-reputable people, like the

   681 ``I did not

   681 infamous ``I did not inhale'' from an US

   682 inhale''.\footnote{\url{www.youtube.com/watch?v=Bktd_Pi4YJw}}

   682 president.\footnote{\url{www.youtube.com/watch?v=Bktd_Pi4YJw}} The

   683 The whole point of the blockchain is that it public and will

   683 whole point of the blockchain is that it public and will always be.

   684 always be. 

   684 

   685 

   685 There are some precautions one can take for boosting anonymity, for

   686 There are some precautions one can take for ensuring anonymity, like

   686 example to use a new public-private key pair for every new

   687 to use a new public-private key pair for every new transaction, and to

   687 transaction, and to access Bitcoin only through the Tor network. But

   688 access Bitcoin only through the Tor network. But the transactions in

   688 the transactions in Bitcoins are designed such that they allow one to

   689 Bitcoins are designed such that they allow one to combine incoming

   689 combine incoming transactions. In such cases we know they must have

   690 transactions. In such cases we know they must have been made by the

   690 been made by the single person who knew the corresponding private

   691 single person who knew the corresponding private keys. So using

   691 keys. So using different public-private keys for each transaction

   692 different public-private keys for each transaction might not actually

   692 might not actually make the de-anonymisation task much harder. And the

   693 make the de-anonymisation task much harder. And the point about

   693 point about de-ano\-nymising `anonymous' social networks is that the

   694 de-ano\-nymising `anonymous' social networks is that the information

   694 information is embedded into the structure of the transition

   695 is embedded into the structure of the transition graph. And this

   695 graph. And this cannot be erased with Bitcoins.

   696 cannot be erased with Bitcoins. 

   696 

   697 

   697 One paper that has fun with spotting transactions made to Silk Road (2.0)

   698 One paper that has fun with spotting transactions to Silk Road (2.0)

   698 and also to Wikileaks is

   699 and to Wikileaks is

   714 Finally, what are the options for a typical western government

   713 Finally, what are the options for a typical Western government to

   715 to meddle with Bitcoins? This is of course one feature the

   714 meddle with Bitcoins? This is of course one feature the proponents of

   716 proponents of Bitcoins also tout: namely that there aren't any

   715 Bitcoins also tout: namely that there aren't any options. In my

   717 options. In my opinion this is far too naive and far from the

   716 opinion this is far too naive and far from the truth. Let us assume

   718 truth. Let us assume some law enforcement agencies would not

   717 some law enforcement agencies would not have been able to uncover the

   719 have been able to uncover the baddies from Silk Road 1.0 and

   718 baddies from Silk Road 1.0 and 2.0 (they have done so by uncovering

   720 2.0 (they have done so by uncovering the Tor network, which is

   719 the Tor network, which is an incredible feat on its own). Would the

   721 an incredible feat on its own). Would a government have

   720 government in question have stopped? I do not think so. The next

   722 stopped? I think no. The next target would have been Bitcoin.

   721 target would have been Bitcoin.  If I were the government, this is

   723 If I were the government, this is what I would consider:

   722 what I would consider:

   726 \item The government could compel ``mayor players'' to

   725 \item The government could compel ``mayor players'' to blacklist

   727       blacklist Bitcoins (for example at Bitcoin exchanges).

   726   Bitcoins (for example at Bitcoin exchanges, which are usually

   728       This would impinge on what is called \emph{fungibility}

   727   located somewhere in the vicinity of the government's reach).  This

   729       of Bitcoins and make them much less attractive to

   728   would impinge on what is called \emph{fungibility} of Bitcoins and

   730       baddies. Suddenly their ``hard-earned'' Bitcoin money cannot

   729   make them much less attractive to baddies. Suddenly their

   731       be spent anymore.The attraction of this option is that

   730   ``hard-earned'' Bitcoin money cannot be spent anymore. The attraction

   732       this blacklisting can be easily done ``whole-sale'' and

   731   of this option is that this blacklisting can be easily done

   733       therefore be really be an attractive target for

   732   ``whole-sale'' and therefore be really be an attractive target for

   734       governments \& Co.      

   733   governments \& Co.

   743       big a miner itself. Given the gigantic facilities that

   742       big miner itself. Given the gigantic facilities that

   753       this would not be such a high bar to jump over. Remember

   752       this would not be such a high bar to jump over. Remember it

   754       it ``only'' takes to be temporarily in control of 50\%+

   753       ``only'' takes to be temporarily in control of 50\%-plus of the

   755       of the mining capacity in order to undermine the trust

   754       mining capacity in order to undermine the trust in the

   756       in the system. Given sophisticated stories like Stuxnet

   755       system. Given sophisticated stories like Stuxnet (where we still

   757       (where we still not know the precise details) maybe even

   756       do not know the precise details) maybe even such large

   758       such large facilities are not really needed. What

   757       facilities are not really needed. What happens, for example, if

   759       happens, for example, if a government starts DoS attacks

   758       a government starts DoS attacks on existing miners? They have

   760       on existing miners: They have complete control

   759       complete control (unfortunately) of all mayor connectivity

   761       (unfortunately) of all mayor connectivity providers,

   760       providers, i.e.~ISPs.

   762       i.e.~ISPs. 

   786 that Bitcoins are free from interference by government \& Co when

   784 that Bitcoins are free from interference by governments \& Co when