There is not yet any exchange that does not keep meticulous track of
   transfers, also due to AML laws.

   A meta-blockchain unfuzzer might still work, as the other coin would
   also use one. Or there'd be central tracking. Or it would be zerocoin!

   As long as zerocoin exists somewhere you can chain-switch (exchange)
   and anonymize.

   On Mar 7, 2014 11:05 PM, "Cathal Garvey"
   <[1]cathalgarvey@cathalgarvey.me> wrote:

     Hey all,
     As it came up in the Mt Gox asides in one of the variously titled
     threads on Nakomoto etc.: Bitcoin's pretty pseudonymous, rather than
     anonymous. Coin transactions are public, and some can be pinned to
     real
     identities, vendors or products, while others can be well inferred,
     leaving a smaller, hard to quantify set of "really anonymous"
     addresses,
     coins and transactions. Added to that, you have coin "taint" and
     badly
     patched wallets that mix coins from other addresses when sending
     payments, correlating various receiving addresses in one single
     transaction.
     There are laundries, but my understanding is that they're not highly
     regarded; their methods may be questionable, potentially they can be
     untangled. Without a large enough set of users, you have little
     guarantee of laundering; if only Alice and Bob pay in, and Alice and
     Bob
     receive out, then the recipient set is clearly too bad to protect
     them!
     OK, big problem. Zerocoin was designed to help fix that problem, by
     minting a zero-knowledge-proof based 'coin, but it hasn't yet been
     implemented.
     What about simply exchanging different blockchain based coins,
     though?
     Would that not help to "launder" with reasonable efficacy, provided
     both
     participants use crypto to hide the transaction? From the outside,
     transactions occur on both blockchains, but there's no "data trail"
     correlating the transactions with one another as there is within
     each
     blockchain.
     So, Alice buys .4 btc from a friend, but knows the friend's opsec
     might
     be poor, or that the transaction may have occurred over a bad
     channel,
     or that the coins were purchased from an exchange that demands valid
     phone numbers, etc.: she wants to launder.
     She contacts Bob, a Dogecoin seller, to set up a private exchange.
     She
     asks him to sell her 0.4btc worth of Dogecoin in two transactions of
     unequal value (to prevent analysis by exchange rate to ID their
     transaction). They conduct the exchange over an encrypted channel.
     >From the outside, someone knows she's laundering, and just bought
     Dogecoin, but because they don't know her Dogecoin receiving
     addresses,
     they've lost the scent; she now has 0.4btc worth of Dogecoin, and
     can
     convert that back to btc again in the same way.
     In a round trip, she's broken the chain; she keeps her value, minus
     fees, of 0.4btc, but now it's in different btc, with no
     blockchain-recorded transaction logs to link the original, tainted
     btc
     to the new, clean btc.
     As a way for an individual to "launder", does this look plausible?
     Is it
     any better or worse than laundries as they currently exist?
     --
     Please help support my crowdfunding campaign, IndieBB: Currently at
     44.8% of funding goal, with 6 days left:
        [2]http://igg.me/at/yourfirstgmo/x/4252296
     T: @onetruecathal, @IndieBBDNA
     P: [3]+3538763663185
     W: [4]http://indiebiotech.com

References

   1. mailto:cathalgarvey@cathalgarvey.me
   2. http://igg.me/at/yourfirstgmo/x/4252296
   3. tel:+3538763663185
   4. http://indiebiotech.com/