Petter Reinholdtsen

Entries tagged "bitcoin".

EU-domstolen konkluderer motsatt av Skatteetaten når det gjelder Bitcoin
22nd October 2015

Bitcoin er i litt vinden i Norge for tiden, med kronikk om bitcoin-overføringer på tvers av landegrensene hos NRK Ytring for to dager siden og dokumentar om bitcoin på NRK 2 i forgårs og i går. I den sammenhengen er det spesielt hyggelig med en gladnyhet fra EU om Bitcoin.

I dag konkluderte EU-domstolen at Bitcoin-kjøp fra Bitcoin-børser ikke er MVA-pliktig (sak C‑264/14). Fant nyheten først hos Reuters, etter tips fra innehaveren av Bitmynt. EU-domstolens avgjørelse er stikk i strid med annonseringen fra Skatteetaten i 2013, der de konkluderte med at bitcoin er et «formuesobjekter» som det skulle betales mva på ved kjøp og salg. Dermed la Skatteetaten opp til dobbel MVA-betaling hvis en kjøpte noe med Bitcoin fra Norge (først mva på kjøp av Bitcoin, deretter mva på det en kjøper med Bitcoin). Jeg lurer på om denne avgjørelsen får Skatteetaten til å bytte mening. Gleder meg til fortsettelsen.

Tags: bitcoin, norsk.
A fist full of non-anonymous Bitcoins
29th January 2014

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 least I would not conduct illegal money transfers using a system where the details of every transaction are kept forever. This point is investigated 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:

"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).

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."

These researches are not the first to analyse the Bitcoin transaction log. The 2011 paper "An Analysis of Anonymity in the Bitcoin System" by Fergal Reid and Martin Harrigan is summarized like this:

"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."

I hope these references can help kill the urban myth that Bitcoin is anonymous. It isn't really a good fit for illegal activites. Use cash if you need to stay anonymous, at least until regular DNA sampling of notes and coins become the norm. :)

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

Tags: bitcoin, english, personvern, sikkerhet, usenix.
Bitcoin er ikke anonymt - føres Stortinget bak lyset av finansministeren?
22nd April 2013

Bitcoin er mye i mediene for tiden. Jeg følger med via Mylder for å finne artikler som omtaler temaet, og takket være dette oppdaget jeg at stortingsrepresentant Ketil Solvik-Olsen fra FrP nylig har spurt finansminister Sigbjørn Johnsen om hans syn på Bitcoin, og fått svar for noen dager siden. Jeg bet meg spesielt merke til følgende formulering fra finansministeren:

«Det er også utfordringer ved at handel med Bitcoins er uregulert og at transaksjonene er anonyme.»

At Bitcoin er anonymt er en myte som spres av både journalister og andre, så det er ikke veldig overraskende at også finansministeren har gått på limpinnen. Det er dog litt rart, da jeg håper at finansdepartementet ikke baserer seg på rykter og myter når de besvarer Stortinget. Men du trenger ikke bare tro på meg som kilde til påstanden om at Bitcoin ikke er anonymt. Sondre Rønjom har via Sikkerhetsbloggen hos Nasjonal Sikkerhetsmyndighet uttalt følgende:

«At [bitcoin] i utgangspunktet ikke er anonymt, kommer kanskje som en overraskelse på mange.»

Enhver bevegelse av Bitcoin er offentlig tilgjengelig for alle på Internet, og en må legge svært mye innsats inn hvis en skal hindre at nettverksanalyse av transaksjonsloggene kan brukes til å identifisere brukerne. F.eks. kan en enkelt se hva jeg har mottatt til min offentliggjorte mottaksadresse ved å besøke blockexplorer og slå opp adressen 15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b. Det virker dermed på meg ganske klart at å påstå at Bitcoin-transaksjoner er anonyme strengt tatt er å føre Stortinget bak lyset.

Finansministeren er ikke den eneste som har latt seg forlede av medieomtalen. I spørsmålet fra Hr. Solvik-Olsen skriver han at «For noen dager siden kom den første bitcoin-minibanken på Kypros», hvilket så vidt jeg har klart å finne ut ikke er riktig. Det er annonsert planer om en slik minibank (fra BitcoinATM), men jeg finner intet tegn til at en slik minibank er utplassert noe sted.

Som vanlig, hvis du bruker Bitcoin og ønsker å vise din støtte til mine aktiviteter, så setter jeg pris på Bitcoin-donasjoner til min adresse 15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b.

Tags: bitcoin, norsk, stortinget.
Bitcoin GUI now available from Debian/unstable (and Ubuntu/raring)
2nd February 2013

My last bitcoin related blog post mentioned that the new bitcoin package for Debian was waiting in NEW. It was accepted by the Debian ftp-masters 2013-01-19, and have been available in unstable since then. It was automatically copied to Ubuntu, and is available in their Raring version too.

But there is a strange problem with the build that block this new version from being available on the i386 and kfreebsd-i386 architectures. For some strange reason, the autobuilders in Debian for these architectures fail to run the test suite on these architectures (BTS #672524). We are so far unable to reproduce it when building it manually, and no-one have been able to propose a fix. If you got an idea what is failing, please let us know via the BTS.

One feature that is annoying me with of the bitcoin client, because I often run low on disk space, is the fact that the client will exit if it run short on space (BTS #696715). So make sure you have enough disk space when you run it. :)

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

Tags: bitcoin, debian, english.
How to backport bitcoin-qt version 0.7.2-2 to Debian Squeeze
25th December 2012

Let me start by wishing you all marry Christmas and a happy new year! I hope next year will prove to be a good year.

Bitcoin, the digital decentralised "currency" that allow people to transfer bitcoins between each other with minimal overhead, is a very interesting experiment. And as I wrote a few days ago, the bitcoin situation in Debian is about to improve a bit. The new debian source package (version 0.7.2-2) was uploaded yesterday, and is waiting in the NEW queue for one of the ftpmasters to approve the new bitcoin-qt package name.

And thanks to the great work of Jonas and the rest of the bitcoin team in Debian, you can easily test the package in Debian Squeeze using the following steps to get a set of working packages:

git clone git://
cd bitcoin
DEB_MAINTAINER_MODE=1 DEB_BUILD_OPTIONS=noupnp fakeroot debian/rules clean
DEB_BUILD_OPTIONS=noupnp git-buildpackage --git-ignore-new

You might have to install some build dependencies as well. The list of commands should give you two packages, bitcoind and bitcoin-qt, ready for use in a Squeeze environment. Note that the client will download the complete set of bitcoin "blocks", which need around 5.6 GiB of data on my machine at the moment. Make sure your ~/.bitcoin/ directory have lots of spare room if you want to download all the blocks. The client will warn if the disk is getting full, so there is not really a problem if you got too little room, but you will not be able to get all the features out of the client.

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

Tags: bitcoin, debian, english.
A word on bitcoin support in Debian
21st December 2012

It has been a while since I wrote about bitcoin, the decentralised peer-to-peer based crypto-currency, and the reason is simply that I have been busy elsewhere. But two days ago, I started looking at the state of bitcoin in Debian again to try to recover my old bitcoin wallet. The package is now maintained by a team of people, and the grunt work had already been done by this team. We owe a huge thank you to all these team members. :) But I was sad to discover that the bitcoin client is missing in Wheezy. It is only available in Sid (and an outdated client from backports). The client had several RC bugs registered in BTS blocking it from entering testing. To try to help the team and improve the situation, I spent some time providing patches and triaging the bug reports. I also had a look at the bitcoin package available from Matt Corallo in a PPA for Ubuntu, and moved the useful pieces from that version into the Debian package.

After checking with the main package maintainer Jonas Smedegaard on IRC, I pushed several patches into the collab-maint git repository to improve the package. It now contains fixes for the RC issues (not from me, but fixed by Scott Howard), build rules for a Qt GUI client package, konqueror support for the bitcoin: URI and bash completion setup. As I work on Debian Squeeze, I also created a patch to backport the latest version. Jonas is going to look at it and try to integrate it into the git repository before uploading a new version to unstable.

I would very much like bitcoin to succeed, to get rid of the centralized control currently exercised in the monetary system. I find it completely unacceptable that the USA government is collecting transaction data for almost all international money transfers (most are done in USD and transaction logs shipped to the spooks), and that the major credit card companies can block legal money transactions to Wikileaks. But for bitcoin to succeed, more people need to use bitcoins, and more people need to accept bitcoins when they sell products and services. Improving the bitcoin support in Debian is a small step in the right direction, but not enough. Unfortunately the user experience when browsing the web and wanting to pay with bitcoin is still not very good. The bitcoin: URI is a step in the right direction, but need to work in most or every browser in use. Also the bitcoin-qt client is too heavy to fire up to do a quick transaction. I believe there are other clients available, but have not tested them.

My experiment with bitcoins showed that at least some of my readers use bitcoin. I received 20.15 BTC so far on the address I provided in my blog two years ago, as can be seen on the blockexplorer service. Thank you everyone for your donation. The blockexplorer service demonstrates quite well that bitcoin is not quite anonymous and untracked. :) I wonder if the number of users have gone up since then. If you use bitcoin and want to show your support of my activity, please send Bitcoin donations to the same address as last time, 15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b.

Tags: bitcoin, debian, english.
The European Central Bank (ECB) take a look at bitcoin
4th November 2012

Slashdot just ran a story about the European Central Bank (ECB) releasing a report (PDF) about virtual currencies and bitcoin. It is interesting to see how a member of the bitcoin community receive the report. As for the future, I suspect the central banks and the governments will outlaw bitcoin if it gain any popularity, to avoid competition. My thoughts go to the Wörgl experiment with negative inflation on cash which was such a success that it was terminated by the Austrian National Bank in 1933. A successful alternative would be a threat to the current money system and gain powerful forces to work against it.

While checking out the current status of bitcoin, I also discovered that the community already seem to have experienced its first pyramid game / Ponzi scheme. Not very surprising, given how members of "small" communities tend to trust each other. I guess enterprising crocks will try again and again, as they do anywhere wealth is available.

Tags: bitcoin, english, personvern, sikkerhet.
Some thoughts on BitCoins
11th December 2010

As I continue to explore BitCoin, I've starting to wonder what properties the system have, and how it will be affected by laws and regulations here in Norway. Here are some random notes.

One interesting thing to note is that since the transactions are verified using a peer to peer network, all details about a transaction is known to everyone. This means that if a BitCoin address has been published like I did with mine in my initial post about BitCoin, it is possible for everyone to see how many BitCoins have been transfered to that address. There is even a web service to look at the details for all transactions. There I can see that my address 15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b have received 16.06 Bitcoin, the 1LfdGnGuWkpSJgbQySxxCWhv8MHqvwst3 address of Simon Phipps have received 181.97 BitCoin and the address 1MCwBbhNGp5hRm5rC1Aims2YFRe2SXPYKt of EFF have received 2447.38 BitCoins so far. Thank you to each and every one of you that donated bitcoins to support my activity. The fact that anyone can see how much money was transfered to a given address make it more obvious why the BitCoin community recommend to generate and hand out a new address for each transaction. I'm told there is no way to track which addresses belong to a given person or organisation without the person or organisation revealing it themselves, as Simon, EFF and I have done.

In Norway, and in most other countries, there are laws and regulations limiting how much money one can transfer across the border without declaring it. There are money laundering, tax and accounting laws and regulations I would expect to apply to the use of BitCoin. If the Skolelinux foundation (SLX Debian Labs) were to accept donations in BitCoin in addition to normal bank transfers like EFF is doing, how should this be accounted? Given that it is impossible to know if money can cross the border or not, should everything or nothing be declared? What exchange rate should be used when calculating taxes? Would receivers have to pay income tax if the foundation were to pay Skolelinux contributors in BitCoin? I have no idea, but it would be interesting to know.

For a currency to be useful and successful, it must be trusted and accepted by a lot of users. It must be possible to get easy access to the currency (as a wage or using currency exchanges), and it must be easy to spend it. At the moment BitCoin seem fairly easy to get access to, but there are very few places to spend it. I am not really a regular user of any of the vendor types currently accepting BitCoin, so I wonder when my kind of shop would start accepting BitCoins. I would like to buy electronics, travels and subway tickets, not herbs and books. :) The currency is young, and this will improve over time if it become popular, but I suspect regular banks will start to lobby to get BitCoin declared illegal if it become popular. I'm sure they will claim it is helping fund terrorism and money laundering (which probably would be true, as is any currency in existence), but I believe the problems should be solved elsewhere and not by blaming currencies.

The process of creating new BitCoins is called mining, and it is CPU intensive process that depend on a bit of luck as well (as one is competing against all the other miners currently spending CPU cycles to see which one get the next lump of cash). The "winner" get 50 BitCoin when this happen. Yesterday I came across the obvious way to join forces to increase ones changes of getting at least some coins, by coordinating the work on mining BitCoins across several machines and people, and sharing the result if one is lucky and get the 50 BitCoins. Check out BitCoin Pool if this sounds interesting. I have not had time to try to set up a machine to participate there yet, but have seen that running on ones own for a few days have not yield any BitCoins througth mining yet.

Update 2010-12-15: Found an interesting criticism of bitcoin. Not quite sure how valid it is, but thought it was interesting to read. The arguments presented seem to be equally valid for gold, which was used as a currency for many years.

Tags: bitcoin, debian, english, personvern, sikkerhet.
Now accepting bitcoins - anonymous and distributed p2p crypto-money
10th December 2010

With this weeks lawless governmental attacks on Wikileak and free speech, it has become obvious that PayPal, visa and mastercard can not be trusted to handle money transactions. A blog post from Simon Phipps on bitcoin reminded me about a project that a friend of mine mentioned earlier. I decided to follow Simon's example, and get involved with BitCoin. I got some help from my friend to get it all running, and he even handed me some bitcoins to get started. I even donated a few bitcoins to Simon for helping me remember BitCoin.

So, what is bitcoins, you probably wonder? It is a digital crypto-currency, decentralised and handled using peer-to-peer networks. It allows anonymous transactions and prohibits central control over the transactions, making it impossible for governments and companies alike to block donations and other transactions. The source is free software, and while the key dependency wxWidgets 2.9 for the graphical user interface is missing in Debian, the command line client builds just fine. Hopefully Jonas will get the package into Debian soon.

Bitcoins can be converted to other currencies, like USD and EUR. There are companies accepting bitcoins when selling services and goods, and there are even currency "stock" markets where the exchange rate is decided. There are not many users so far, but the concept seems promising. If you want to get started and lack a friend with any bitcoins to spare, you can even get some for free (0.05 bitcoin at the time of writing). Use BitcoinWatch to keep an eye on the current exchange rates.

As an experiment, I have decided to set up bitcoind on one of my machines. If you want to support my activity, please send Bitcoin donations to the address 15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b. Thank you!

Tags: bitcoin, debian, english, personvern, sikkerhet.

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