Hal writes: [suggesting a problem with Ed the Currency Cleaner]
What about this, though: Alice did not mean to pay Bob, but rather Charlie, and Bob stole the coins. He launders them through Ed's service. Charlie never got the cash, and Alice complains to the bank that the coins were stolen. The bank says, fine, we can identify the perpetrator, let's see... it's Ed. Ed is now charged with theft and has an expensive and uncertain legal experience ahead of him.
Jumping in hastily: It seems to me that Ed faces a larger problem if the above scenario turns out to be a viable attack. Consider the following sequence: Alice and Charlie decide to get some (payee-anonymous) currency laundromat in hot water. Alice (payer-anonymously) washes some coins at the laundromat. Con-man Charlie claims he didn't get paid for some fictional transaction with Alice. Alice complains to the bank, and the rest proceeds as before. The Alice-frames-Ed situation is functionally equivalent to the Bob-robs-Charlie situation from the bank's perspective. -Futplex <futplex@pseudonym.com>