Topic: Blockchain.info misreports origins (Was:Swiss University jumps into mining game) - page 5. (Read 21274 times)

... Until now, double-spending attacks on fast pay-
ments in Bitcoin or mechanisms for their prevention
have not been studied. In this work, we analyze
double spending attacks in detail and we demon-
strate that double-spending attacks can be mounted
on currently deployed version of Bitcoin, when used
in fast payments. We further show that the measures
recommended by Bitcoin developers for fast trans-
actions are not always effective in resisting double-
spending; we argue that if those recommendations
are followed, double-spending attacks on Bitcoin
are still possible. Finally, we propose a lightweight
countermeasure to detect double-spending attacks in
fast transactions.

More specifically, our contributions in this paper
can be summarized as follows:

We measure and analyze the time required to con-
firm transactions in Bitcoin. Our analysis shows
that transaction confirmation in Bitcoin can be
modeled with a shifted geometric distribution and
that, although the average time to confirm transac-
tions is almost 10 minutes, its standard deviation is
approximately 15 minutes. We argue that this hin-
ders the reliance of transaction confirmation when
dealing with fast payment scenarios.

We thoroughly analyze the conditions for perform-
ing successful double-spending attacks against fast
payments in Bitcoin. We then present the first
comprehensive double-spending measurements in
Bitcoin. Our experiments were conducted us-
ing modified Bitcoin clients running on a hand-
ful of hosts located around the globe. Our results
demonstrate the feasibility and easy realization of
double-spending attacks in current Bitcoin client
implementations.

We explore and evaluate empirically a number of
solutions for preventing double-spending attacks
against fast payments in Bitcoin. We show that the
recommendations of Bitcoin developers on how to
counter double-spending are not always effective.
Leveraging on our results, we propose a lightweight
countermeasure that enables the secure verification
of fast payments. ...

I don't understand what in the translated paper. Do they have great hashing power or discovered a flaw in the bitcoin protocol?

Swiss... they have something to defend

it doesn't matter if the party is "good" or "bad". every party has to be rejected if they have more than 50% of the network if it was the case.

This is not a bad thing. That is a legitimate organization, they are not doing it with hostile intent. Very interesting though!

Where do i find this paper?

Are the bitcoin core developers in communication with ETH Zürich? (Capkun, Androulaki, Karami.)

Bitcoin is a decentralized payment system that is
based on Proof-of-Work. Bitcoin is currently gaining
popularity as a digital currency; several businesses
are starting to accept Bitcoin transactions.
An example case of the growing use of Bitcoin was recently
reported in the media; here, Bitcoins were used as a
form of fast payment in a local fast-food restaurant.

In this paper, we analyze the security of using
Bitcoin for fast payments, where the time between
the exchange of currency and goods is short (i.e.,
in the order of few seconds). We focus on doublespending attacks on fast payments and demonstrate
that these attacks can be mounted at low cost on
currently deployed versions of Bitcoin. We further
show that the measures recommended by Bitcoin developers for the use of Bitcoin in fast transactions are
not always effective in resisting double-spending; we
show that if those recommendations are integrated
in future Bitcoin implementations, double-spending
attacks on Bitcoin will still be possible. Finally, we
leverage on our findings and propose a lightweight
countermeasure that enables the detection of doublespending attacks in fast transactions.

they wrote a paper about Bitcoin some days ago

How do you know it's not just relaying someone's blocks ?