From: Petter Reinholdtsen Date: Wed, 29 Jan 2014 13:05:35 +0000 (+0000) Subject: New post. X-Git-Url: https://pere.pagekite.me/gitweb/homepage.git/commitdiff_plain/7c3835c47e8f99ed8de332652241959d39087638?ds=sidebyside New post. --- diff --git a/blog/data/2014-01-29-bitcoin.txt b/blog/data/2014-01-29-bitcoin.txt new file mode 100644 index 0000000000..5264b0a996 --- /dev/null +++ b/blog/data/2014-01-29-bitcoin.txt @@ -0,0 +1,78 @@ +Title: A fist full of non-anonymous Bitcoins +Tags: english, bitcoin +Date: 2014-01-29 14:10 + +

Bitcoin is a incredible use of peer to peer communication and +encryption, allowing direct and immediate money transfer without any +central control. It is sometimes claimed to be ideal for illegal +activity, which I believe is quite a long way from the truth. At last +I would not conduct illegal money transfers using a system where the +details of every transaction is kept forever. This point is +investigated in an peer reviewed article in USENIX ;login: from +December 2013, in the article +A +Fistful of Bitcoins - Characterizing Payments Among Men with No +Names by Sarah Meiklejohn, Marjori Pomarole,Grant Jordan, Kirill +Levchenko, Damon McCoy, Geoffrey M. Voelker, and Stefan Savage. They +analyse the transaction log in the Bitcoin system, using it to find +addresses belong to individuals and organisations and follow the flow +of money from both Bitcoin theft and trades on Silk Road to where the +money end up. This is how they wrap up their article:

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To demonstrate the usefulness of this type of analysis, we turned +our attention to criminal activity. In the Bitcoin economy, criminal +activity can appear in a number of forms, such as dealing drugs on +Silk Road or simply stealing someone else’s bitcoins. We followed the +flow of bitcoins out of Silk Road (in particular, from one notorious +address) and from a number of highly publicized thefts to see whether +we could track the bitcoins to known services. Although some of the +thieves attempted to use sophisticated mixing techniques (or possibly +mix services) to obscure the flow of bitcoins, for the most part +tracking the bitcoins was quite straightforward, and we ultimately saw +large quantities of bitcoins flow to a variety of exchanges directly +from the point of theft (or the withdrawal from Silk Road).

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As acknowledged above, following stolen bitcoins to the point at +which they are deposited into an exchange does not in itself identify +the thief; however, it does enable further de-anonymization in the +case in which certain agencies can determine (through, for example, +subpoena power) the real-world owner of the account into which the +stolen bitcoins were deposited. Because such exchanges seem to serve +as chokepoints into and out of the Bitcoin economy (i.e., there are +few alternative ways to cash out), we conclude that using Bitcoin for +money laundering or other illicit purposes does not (at least at +present) seem to be particularly attractive.

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These researches are not the first to analyse the Bitcoin +transaction log. The 2001 paper +An Analysis of Anonymity in +the Bitcoin System by Fergal Reid and Martin Harrigan is +summarized like this:

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+Anonymity in Bitcoin, a peer-to-peer electronic currency system, is a +complicated issue. Within the system, users are identified by +public-keys only. An attacker wishing to de-anonymize its users will +attempt to construct the one-to-many mapping between users and +public-keys and associate information external to the system with the +users. Bitcoin tries to prevent this attack by storing the mapping of +a user to his or her public-keys on that user's node only and by +allowing each user to generate as many public-keys as required. In +this chapter we consider the topological structure of two networks +derived from Bitcoin's public transaction history. We show that the +two networks have a non-trivial topological structure, provide +complementary views of the Bitcoin system and have implications for +anonymity. We combine these structures with external information and +techniques such as context discovery and flow analysis to investigate +an alleged theft of Bitcoins, which, at the time of the theft, had a +market value of approximately half a million U.S. dollars. +

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I hope these references can help kill the urban myth that Bitcoin +are anonymous.

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As usual, if you use bitcoin and want to show your support of my +activities, please send Bitcoin donations to my address +15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b.