blog/archive/2014/01/01.rss

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   4                 <title>Petter Reinholdtsen - Entries from January 2014</title>
   5                 <description>Entries from January 2014</description>
   6                 <link>http://people.skolelinux.org/pere/blog/</link>
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   9         <item>
  10                 <title>A fist full of non-anonymous Bitcoins</title>
  11                 <link>http://people.skolelinux.org/pere/blog/A_fist_full_of_non_anonymous_Bitcoins.html</link>
  12                 <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/A_fist_full_of_non_anonymous_Bitcoins.html</guid>
  13                 <pubDate>Wed, 29 Jan 2014 14:10:00 +0100</pubDate>
  14                 <description>&lt;p&gt;Bitcoin is a incredible use of peer to peer communication and
  15 encryption, allowing direct and immediate money transfer without any
  16 central control.  It is sometimes claimed to be ideal for illegal
  17 activity, which I believe is quite a long way from the truth.  At least
  18 I would not conduct illegal money transfers using a system where the
  19 details of every transaction are kept forever.  This point is
  20 investigated in
  21 &lt;a href=&quot;https://www.usenix.org/publications/login&quot;&gt;USENIX ;login:&lt;/a&gt;
  22 from December 2013, in the article
  23 &quot;&lt;a href=&quot;https://www.usenix.org/system/files/login/articles/03_meiklejohn-online.pdf&quot;&gt;A
  24 Fistful of Bitcoins - Characterizing Payments Among Men with No
  25 Names&lt;/a&gt;&quot; by Sarah Meiklejohn, Marjori Pomarole,Grant Jordan, Kirill
  26 Levchenko, Damon McCoy, Geoffrey M. Voelker, and Stefan Savage.  They
  27 analyse the transaction log in the Bitcoin system, using it to find
  28 addresses belong to individuals and organisations and follow the flow
  29 of money from both Bitcoin theft and trades on Silk Road to where the
  30 money end up.  This is how they wrap up their article:&lt;/p&gt;
  31
  32 &lt;p&gt;&lt;blockquote&gt;
  33 &lt;p&gt;&quot;To demonstrate the usefulness of this type of analysis, we turned
  34 our attention to criminal activity. In the Bitcoin economy, criminal
  35 activity can appear in a number of forms, such as dealing drugs on
  36 Silk Road or simply stealing someone else’s bitcoins. We followed the
  37 flow of bitcoins out of Silk Road (in particular, from one notorious
  38 address) and from a number of highly publicized thefts to see whether
  39 we could track the bitcoins to known services. Although some of the
  40 thieves attempted to use sophisticated mixing techniques (or possibly
  41 mix services) to obscure the flow of bitcoins, for the most part
  42 tracking the bitcoins was quite straightforward, and we ultimately saw
  43 large quantities of bitcoins flow to a variety of exchanges directly
  44 from the point of theft (or the withdrawal from Silk Road).&lt;/p&gt;
  45
  46 &lt;p&gt;As acknowledged above, following stolen bitcoins to the point at
  47 which they are deposited into an exchange does not in itself identify
  48 the thief; however, it does enable further de-anonymization in the
  49 case in which certain agencies can determine (through, for example,
  50 subpoena power) the real-world owner of the account into which the
  51 stolen bitcoins were deposited.  Because such exchanges seem to serve
  52 as chokepoints into and out of the Bitcoin economy (i.e., there are
  53 few alternative ways to cash out), we conclude that using Bitcoin for
  54 money laundering or other illicit purposes does not (at least at
  55 present) seem to be particularly attractive.&quot;&lt;/p&gt;
  56 &lt;/blockquote&gt;&lt;p&gt;
  57
  58 &lt;p&gt;These researches are not the first to analyse the Bitcoin
  59 transaction log.  The 2011 paper
  60 &quot;&lt;a href=&quot;http://arxiv.org/abs/1107.4524&quot;&gt;An Analysis of Anonymity in
  61 the Bitcoin System&lt;/A&gt;&quot; by Fergal Reid and Martin Harrigan is
  62 summarized like this:&lt;/p&gt;
  63
  64 &lt;p&gt;&lt;blockquote&gt;
  65 &quot;Anonymity in Bitcoin, a peer-to-peer electronic currency system, is a
  66 complicated issue. Within the system, users are identified by
  67 public-keys only. An attacker wishing to de-anonymize its users will
  68 attempt to construct the one-to-many mapping between users and
  69 public-keys and associate information external to the system with the
  70 users. Bitcoin tries to prevent this attack by storing the mapping of
  71 a user to his or her public-keys on that user&#39;s node only and by
  72 allowing each user to generate as many public-keys as required. In
  73 this chapter we consider the topological structure of two networks
  74 derived from Bitcoin&#39;s public transaction history. We show that the
  75 two networks have a non-trivial topological structure, provide
  76 complementary views of the Bitcoin system and have implications for
  77 anonymity. We combine these structures with external information and
  78 techniques such as context discovery and flow analysis to investigate
  79 an alleged theft of Bitcoins, which, at the time of the theft, had a
  80 market value of approximately half a million U.S. dollars.&quot;
  81 &lt;/blockquote&gt;&lt;/p&gt;
  82
  83 &lt;p&gt;I hope these references can help kill the urban myth that Bitcoin
  84 is anonymous.  It isn&#39;t really a good fit for illegal activites.  Use
  85 cash if you need to stay anonymous, at least until regular DNA
  86 sampling of notes and coins become the norm. :)&lt;/p&gt;
  87
  88 &lt;p&gt;As usual, if you use Bitcoin and want to show your support of my
  89 activities, please send Bitcoin donations to my address
  90 &lt;b&gt;&lt;a href=&quot;bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&quot;&gt;15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&lt;/a&gt;&lt;/b&gt;.&lt;/p&gt;
  91 </description>
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  95                 <title>New chrpath release 0.16</title>
  96                 <link>http://people.skolelinux.org/pere/blog/New_chrpath_release_0_16.html</link>
  97                 <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/New_chrpath_release_0_16.html</guid>
  98                 <pubDate>Tue, 14 Jan 2014 11:00:00 +0100</pubDate>
  99                 <description>&lt;p&gt;&lt;a href=&quot;http://www.coverity.com/&quot;&gt;Coverity&lt;/a&gt; is a nice tool to
 100 find problems in C, C++ and Java code using static source code
 101 analysis.  It can detect a lot of different problems, and is very
 102 useful to find memory and locking bugs in the error handling part of
 103 the source.  The company behind it provide
 104 &lt;a href=&quot;https://scan.coverity.com/&quot;&gt;check of free software projects as
 105 a community service&lt;/a&gt;, and many hundred free software projects are
 106 already checked.  A few days ago I decided to have a closer look at
 107 the Coverity system, and discovered that the
 108 &lt;a href=&quot;http://www.gnu.org/software/gnash/&quot;&gt;gnash&lt;/a&gt; and
 109 &lt;a href=&quot;http://sourceforge.net/projects/ipmitool/&quot;&gt;ipmitool&lt;/a&gt;
 110 projects I am involved with was already registered.  But these are
 111 fairly big, and I would also like to have a small and easy project to
 112 check, and decided to &lt;a href=&quot;http://scan.coverity.com/projects/1179&quot;&gt;request
 113 checking of the chrpath project&lt;/a&gt;.  It was
 114 added to the checker and discovered seven potential defects.  Six of
 115 these were real, mostly resource &quot;leak&quot; when the program detected an
 116 error.  Nothing serious, as the resources would be released a fraction
 117 of a second later when the program exited because of the error, but it
 118 is nice to do it right in case the source of the program some time in
 119 the future end up in a library.  Having fixed all defects and added
 120 &lt;a href=&quot;https://lists.alioth.debian.org/mailman/listinfo/chrpath-devel&quot;&gt;a
 121 mailing list for the chrpath developers&lt;/a&gt;, I decided it was time to
 122 publish a new release.  These are the release notes:&lt;/p&gt;
 123
 124 &lt;p&gt;New in 0.16 released 2014-01-14:&lt;/p&gt;
 125
 126 &lt;ul&gt;
 127
 128   &lt;li&gt;Fixed all minor bugs discovered by Coverity.&lt;/li&gt;
 129   &lt;li&gt;Updated config.sub and config.guess from the GNU project.&lt;/li&gt;
 130   &lt;li&gt;Mention new project mailing list in the documentation.&lt;/li&gt;
 131
 132 &lt;/ul&gt;
 133
 134 &lt;p&gt;You can
 135 &lt;a href=&quot;https://alioth.debian.org/frs/?group_id=31052&quot;&gt;download the
 136 new version 0.16 from alioth&lt;/a&gt;.  Please let us know via the Alioth
 137 project if something is wrong with the new release.  The test suite
 138 did not discover any old errors, so if you find a new one, please also
 139 include a test suite check.&lt;/p&gt;
 140 </description>
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