
An Analysis of Anonymity in the Bitcoin System - dfc
http://anonymity-in-bitcoin.blogspot.com/
======
randomwalker
Previous discussion: <http://news.ycombinator.com/item?id=2800790>

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Qweef
The author goes to great lenghts to analyze transactions, yet he fails to
reveal even a single name.

Bitcoin is not anonymous, but finding out who did what is damn hard.

~~~
feral
There are two authors.

We made a decision not to reveal names (or forum names, etc), because we are
doing academic research here. Our motivation is to let people know they aren't
inherently anonymous when they use Bitcoin, rather than to publicly compromise
the privacy of as many individuals as we can.

We could have published a mapping between information we had (typically
bitcoin forum usernames, twitter handles, lists of names of organisations) and
sets of bitcoin addresses. This would probably have made our point in a
harder-to-argue-with way, but probably wouldn't be a good thing to do.

Of course we don't typically have names and addresses of the people using
Bitcoin.

We weren't interested in arguing that its often possible to go from, say,
forum IDs, or twitter accounts, to names and addresses. I suspect everyone
knows that.

What we were trying to show is that Bitcoin doesn't automatically hide your
identity, and that a lot of activity on Bitcoin, that seems superficially hard
to analyse, can actually be analysed. Our point was that a lot of people might
think the Bitcoin system is making them anonymous, because they are often
using different Bitcoin addresses, but that people had better be careful (say,
if they are using Bitcoin while living in a repressive regime) because its
much easier to link your different addresses than you might think.

~~~
derefr
You could release a list of hashes with a known input format corresponding to
(name, key) tuples. That way, any individual could check whether their own key
had been de-anonymized by your analysis, without creating a public mapping
between the two.

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feral
Whats this doing on the front page, again?

I'm one of the authors, if another discussion does start here, I'll be happy
to try and answer questions.

~~~
nas
HN has a love/hate relationship with bitcoin? :-/

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rasengan
[http://coderrr.wordpress.com/2011/06/30/patching-the-
bitcoin...](http://coderrr.wordpress.com/2011/06/30/patching-the-bitcoin-
client-to-make-it-more-anonymous/)

This is important, if you would like to be anonymous (along with a few other
tools).

~~~
feral
We mention this patch, in an updated version of our work (currently under
review, and not yet online).

This patch goes a substantial way to mitigating one of the big issues we
discuss; the issue is that, in the protocol, separate balances, when used as
inputs to the same transaction, are revealed to be controlled by the same
individual.

As the official client does not allow balances to be selected individually,
many of the addresses within a wallet end up being revealed to be controlled
by the same individual user, which users do not expect; this patch goes a long
way towards fixing that.

I still would not assume it is sufficient to guarantee anonymity, with
Bitcoin. There may be other forms of information leakage that allow accounts
be linked, or linked with a certain degree of confidence, but the fact that it
shows key linking to users, will go a long way towards helping users
understand that they may have linked accounts without meaning to.

------
jerguismi
Bitcoin is not anonymous, true. But with skilled and careful use, it can be
made perfectly anonymous.

~~~
loeg
No.

