Greetings. So I've been trying to figure out what exactly zerocoin is etc and since you guys seem to be the only ones actually doing anything with it, I'm hoping you can answer my questions about it.
1. The first question is about this statement "Using 8 cores on a 2.4GHz Core i7, Zerocoin spend transactions would take about 3 seconds to generate, and about 0.5 s to verify." What sort of time frames would that be for more a "mainsteam" system like maybe an I3. Or, and this wasn't clear to me from the various things I was reading, are those transactions actually done by the miners and so it doesn't actually apply to regular users?
2. Is zerocoin basically just a "mixer"? i.e. you can't actually do transactions with other people with them? The zerocoin site is somewhat confusing as it talks about both zerocoin and zerocash but everytime it talks about transactions, it references zerocash. In addition, the zerocoin whitepaper's example is of a person minting and then collecting their own coins.
3. Is there a record on the blockchain of how many coins an address minted or collected? It would seem to me that one way or another, there would be a balance reflected on the blockchain that others could see. So let's say I wasn't all that bright and I minted 133t coins from one wallet address and collected l337 coins on another. In this case it wouldn't be all that hard to "track" what I was doing correct?
Here are some partial answers:
1. Not sure, but lets say that on an old system the times are 10 times slower: half a minute seems like a small price to pay for anonymity.
2. Zerocoin is in effect a mixing pool. However, the mixing pool contains everyone who ever bought a zerocoin. The size of this mixing pool will be many orders of magnitude larger than those used with other coins.
3. You are right about this example. I suspect that the wallet will have a check to make sure that the user doesn't do something stupid like that. Another potential problem is a timing analysis. If you buy some zerocoins, and then immediately redeem only a portion of them, this might look suspicious in the block chain. As far as i know, these are the only flaws with the zerocoin model: timing analysis, and minting/spending the exact same amount.