http://www.flamewars.org/~phil/Bitcoin%20mixnet.pdf

From the linked document:

Bitcoin recipients can have perfect anonymity: they can create a new address at any time to receive a payment and there's nothing to connect that address to the recipient's identity or other Bitcoin addresses. Senders have to work harder to achieve that objective.

If we assume that participants can use existing anonymizing networks to exchange messages, we can design a mixnet to provide payment senders with the ability to send coins without identifying themselves.

This idea or one like it has very likely been discussed before. I've certainly seen people suggesting using Bitcoin exchanges as single-stage coin exchangers to limit the traceability of a transaction. This is mainly a suggestion for how to standardize that concept to allow for a scalable mixnet. It's a very rough and general document at the moment, but I think it's a good starting point for discussion.

I'm new to bitcoin and I have a few questions I hope someone can answer. I've been reading everything I can find but it seems like a lot of the documentation and technical information is scattered in many different places, so I apologize if these have been answered before. If you have a link to any relevant information I might have missed please let me know.

I'm a little confused about how things work with the wallet.dat file. I've read that it needs to be backed up frequently and that it contains 100 pre-generated keys which are used up by transactions, so that a new key is generated after each transaction. I've also read that your bitcoin addresses can receive payments while the bitcoin client isn't running. To me that seems like it contains some internal contradictions but that might just be my ignorance. Is there a limit on the number of payments you can receive while the client isn't running? For example if you receive more than 100 payments will you run out of keys, or is it OK because the client will just generate new ones as it processes the transactions once you finally run it? Are those 100 keys published into the network at all, or just stored in the wallet?

Can I run clients on multiple computers simultaneously using the same wallet.dat?

Secondly, I'm given to understand that all transactions in the bitcoin network are public, that the block chain effectively contains the complete ownership history of each coin since it was created. So, how can I examine that history? I thought there might be something like this in the RPC API but the documentation doesn't mention it. Is there software that does this? Or am I confused about how this actually works?