Nxt :: NXTcash - progress and discussion

[jl777]

I guess proceed with your experiment. You may learn new helpful insights in the process. Best wishes. I've added your name to list of developers to contact soon.

Thanks!

So, basic concept is sound? Would you say NXTmixer could be a bit better than zerocoin?

Sound up to your scaling limits but we must trust your server is honest which is the antithesis of decentralized currency.

Zerocoin has flaws I enumerated. And it targets a different problem, which is long-term anonymity of the blockchain.

Your mixer is perfectly obscuring the IP address (assuming the server is honest), which is also necessary but can't possibly address the long-term leakage of identities.

In short, we need both. And we need to fix all the issues. As far as I know, no one has yet published how to do that.

My approach for NXTcash requires using a separate location to cash in the minted zerocoins and funding a totally new account. by using that account for the payment account in NXTmixer I think we get both cleanly integrated.

I think the biggest problem is user error and inadvertently creating a link between accounts that should be separate. By adding a layer of software to manage access, it should be possible to ensure the user doesnt goof up

James

If I see 24.79 spent and later 24.79 credited. It doesn't matter what you hide in between, I can still correlate them. Even if the user splits the amounts, i.e. 24.79 spent then 13.38 and 11.41 get credited to separate accounts, pattern analysis may still identify them.

So obscuring the process in the middle with a mixer that obscures IP address and/or links between spends and credits doesn't necessarily provide anonymity.

Using constant amounts (e.g. 0.001 BTC, 0.1 BTC, 1 BTC, 10 BTC) with the Zerocoin mixer would provide a much larger anonymity set, but only if these split amounts aren't recombined into a credit to one address.

Thus the multiple inputs for a transaction in Bitcoin can be considered a flaw in this application.

But imagine how much more complicated your wallet becomes will 1000s of keys. Perhaps hierarchical deterministic wallets is a solution.

What if the user never directly touches the "shadow" accts after initial funding?
all payments and deposits are under encryption, so all that is known is that money went into the shadow economy, but nothing else as long as the shadow acct is never linked to normal acct

The activity with the shadow accts are visible, but with all the spending under encryption, no correlation to who is controlling it.

You will see $24.79 appear in an acct, but nobody knows whose acct it is.

[jl777]

If I see 24.79 spent and later 24.79 credited. It doesn't matter what you hide in between, I can still correlate them. Even if the user splits the amounts, i.e. 24.79 spent then 13.38 and 11.41 get credited to separate accounts, pattern analysis may still identify them.

So obscuring the process in the middle with a mixer that obscures IP address and/or links between spends and credits doesn't necessarily provide anonymity.

The acct which receives payment is never revealed in the clear. Neither are the accts that send the payments.

The initial condition where nobody has any funds is tricky and still a bit unsolved, but at worst a bunch of people send to the mixer the same amount and it funds each persons shadow acct.

From then on, payments are encrypted, the destination is not correlated with the normal acct of the recipient, etc.

This is more than normal mixing with the indirections on both sending and receiving

Edit: just to make it that much harder to correlate, payments can be broken up into standard denominations and stretched out over several sessions, this would be useful for larger payments that would have a hard time blending. Maybe a globally determined max that can be sent based on the sessions exact transactions

[lexxus]

Do you need testers/developers?

[l8orre]

guys- just do start something  - can be moved elsewhere later.

testCase2 - sending 10 BID orders with time delay of 10ms to NRS - result: ONE BID order on the order book, 10 identical requests sent.

so sending ten identical BID order queries is processed as one only by NRS



########### balances before start:
bal: 1698833
unconfBal: 1617955
effBal: 1698800




emitter - nxtUCTest2 here

timestamp - 1394895608.0248673

queryNum - 9

fullQuery - {'asset': '16739598998421896224', 'deadline': 180, 'secretPhrase': 'xxxxxxxxxxxxxxxx', 'price': 100, 'fee': 1, 'requestType': 'placeBidOrder', 'quantity': 1}

########### NRS Reply:

transaction = 4525878627944622113
 balances during testt:

( repeat 9x)

[Ziggy]

800 nxt sent
Transaction id: 11665090002745715591

good luck!

[Armando]

I guess proceed with your experiment. You may learn new helpful insights in the process. Best wishes. I've added your name to list of developers to contact soon.

Thanks!

So, basic concept is sound? Would you say NXTmixer could be a bit better than zerocoin?

Sound up to your scaling limits but we must trust your server is honest which is the antithesis of decentralized currency.

Zerocoin has flaws I enumerated. And it targets a different problem, which is long-term anonymity of the blockchain.

Your mixer is perfectly obscuring the IP address (assuming the server is honest), which is also necessary but can't possibly address the long-term leakage of identities.

In short, we need both. And we need to fix all the issues. As far as I know, no one has yet published how to do that.

My approach for NXTcash requires using a separate location to cash in the minted zerocoins and funding a totally new account. by using that account for the payment account in NXTmixer I think we get both cleanly integrated.

I think the biggest problem is user error and inadvertently creating a link between accounts that should be separate. By adding a layer of software to manage access, it should be possible to ensure the user doesnt goof up

James

If I see 24.79 spent and later 24.79 credited. It doesn't matter what you hide in between, I can still correlate them. Even if the user splits the amounts, i.e. 24.79 spent then 13.38 and 11.41 get credited to separate accounts, pattern analysis may still identify them.

Never used coin mixers, but I suppose they will take some fees? So if you'll send them 24.79, you'll get back less. I can't imagine someone will run such service, that can be heavily used by criminals, for free or I don't understand something?

PS: As for this project, development of decentralized anonymous transactions seems legit enterprise for me, but I can be wrong of course

[-Greed-]

Any progress yet?

[jl777]

Any progress yet?

Building the foundation while waiting for some external developments that will really help this project, like the new zerocash and Parallel Chains

discussion has been moved to: https://nxtforum.org/multigateway-(third-party)/nxtcash-and-nxtmixer/

James