Bitcoin Forum

Bitcoin => Project Development => Topic started by: SmokeTooMuch on February 27, 2011, 01:31:35 PM



Title: Bitcoin Proxy Concept - does it work ?
Post by: SmokeTooMuch on February 27, 2011, 01:31:35 PM
http://anonymouse.org/cgi-bin/anon-www.cgi/http://img710.imageshack.us/img710/1758/diagram1y.jpg

this way recipents would only see the "mix proxy address" and transactions can't be assigned to the users since neither timing attack nor checking for amounts would work.

is this correct ?


EDIT: image is not online anymore


Title: Re: Bitcoin Proxy Concept - does it work ?
Post by: SmokeTooMuch on February 27, 2011, 02:06:56 PM
Hmm, it comes pretty close to BitLaundry (https://bitlaundry.appspot.com/explanation)

Quote
BitLaundry Explanation
BitLaundry is designed to help unlink accounts from each other. It does that by providing a well-known, and hopefully popular service. Here's how it works:

   1. Imagine that Alice wishes to send BitCoins to Bob.
   2. Bob, sadly, is not well liked. Alice would rather not have anyone know that she sent Bob BitCoins.
   3. So, Alice puts Bob's address in the form at BitLaundry.
   4. Alice gets a one-time-use address from BitLaundry.
   5. Alice sends the money to that address.
   6. BitLaundry sends money out to recipients every 30 minutes.
   7. (But, it doesn't send out Alice's money immediately, that might be suspicious..)
   8. So, a random number of 30 minute segments later, BitLaundry sends the money out to Bob.
   9. BitLaundry then deletes the database link between the one-time-use address and Bob.
  10. Alice has sent money to BitLaundry, but people do this all the time. She's one of many.
  11. BitLaundry has sent money to Bob, but BitLaundry has sent money out to a whole bunch of other people as well.
  12. Alice and Bob are much less linked than they would have been otherwise.

But as I understand it, you can track Alice by looking at the block chain and look for the amount that Bob received by BitLaundry.
Then you check which address sent this amount to BitLaundry (probably one of the one-time-use addresses from step 4) and then check which address sended that amount to the one-time-use address.
Is that correct ?


Title: Re: Bitcoin Proxy Concept - does it work ?
Post by: BioMike on February 27, 2011, 03:38:12 PM
To solve the timing problem, the amount should be split into various (random?) amounts and then send at different time points. There could be a few same entries of the same value in the database (created when Alice adds her bitcoins for Bob) that are send at the same time to different addresses (owned by the laundry, but nobody knows that)). In the end the laundry sends money to the receivers and to itself.


Title: Re: Bitcoin Proxy Concept - does it work ?
Post by: markm on February 27, 2011, 04:43:17 PM
It seems to me from what I have learned so far about bitcoin that all of this should probably be done for Alice by thispackageisnotforlaunderingmoney software installed on her own machine, as I get the impression nothing in the blockchain records indicates whether more than one machine wrote any part of the block chain.

So why set someone else up to take the rap for laundering your money? Have cron run as many Non-Player Character accounts as you think will create sufficient illusion that there are more people playing this game than just you, the satoshi A.I. and we forum-elizabots.

It would help to have the full 8 decimals to play with of course, because then you could simulate a 99,999,999 address market by moving around less than one bitcoin.

-MarkM- (Lets make miners buy bigger disks by generating oodles of transactions for fun and not for laundering money officer no sir not me...)




Title: Re: Bitcoin Proxy Concept - does it work ?
Post by: FooDSt4mP on February 27, 2011, 06:00:33 PM
Hmm, it comes pretty close to BitLaundry (https://bitlaundry.appspot.com/explanation)

Quote
BitLaundry Explanation
BitLaundry is designed to help unlink accounts from each other. It does that by providing a well-known, and hopefully popular service. Here's how it works:

   1. Imagine that Alice wishes to send BitCoins to Bob.
   2. Bob, sadly, is not well liked. Alice would rather not have anyone know that she sent Bob BitCoins.
   3. So, Alice puts Bob's address in the form at BitLaundry.
   4. Alice gets a one-time-use address from BitLaundry.
   5. Alice sends the money to that address.
   6. BitLaundry sends money out to recipients every 30 minutes.
   7. (But, it doesn't send out Alice's money immediately, that might be suspicious..)
   8. So, a random number of 30 minute segments later, BitLaundry sends the money out to Bob.
   9. BitLaundry then deletes the database link between the one-time-use address and Bob.
  10. Alice has sent money to BitLaundry, but people do this all the time. She's one of many.
  11. BitLaundry has sent money to Bob, but BitLaundry has sent money out to a whole bunch of other people as well.
  12. Alice and Bob are much less linked than they would have been otherwise.

But as I understand it, you can track Alice by looking at the block chain and look for the amount that Bob received by BitLaundry.
Then you check which address sent this amount to BitLaundry (probably one of the one-time-use addresses from step 4) and then check which address sended that amount to the one-time-use address.
Is that correct ?


I think this would require that BitLaundry's wallet.dat be compromised in order to know the one-time-use address even belonged to them.


Title: Re: Bitcoin Proxy Concept - does it work ?
Post by: sandos on February 27, 2011, 09:01:38 PM
It seems to me from what I have learned so far about bitcoin that all of this should probably be done for Alice by thispackageisnotforlaunderingmoney software installed on her own machine, as I get the impression nothing in the blockchain records indicates whether more than one machine wrote any part of the block chain.

This doesn't matter, you have to consider the fact that "owning" a whole lot of the network connections is fairly easy, and given that you can add that info yourself depending on where in the network the protocol commands came from. Might work if you do it yourself, split into multiple actions, every action done via Tor and different end-points.