verify ownership of addresses and past transactions

[zef]

Kind of a vague title, and actually i know there has been discussion on the forums and elsewhere about this, but I was unable to find a reasonable solution to this problem as it stands now:

If someone does not want to be anonymous, ie prove to someone else that he owns a specific address or list of addresses of past transactions, how can one achieve this in a way that does not compromise a wallet?

For instance if I as a seller had a successful transaction with buyer A using address X, and wanted to prove to new buyer B that I was the owner of address X in order to build trust, how can buyer B verify this with out sending money to address X, etc?

On the flip side of this, how can a buyer prove that he sent money to someone using a specific address?  And is there even a way to send money from a specific address you own?

Right now as I understand things it seems the only way to verify ownership of an address would be to have access to the physical wallet, or have the verifier send a random amount of coin to an address and have the unverified person respond with the amount.  Please enlighten me!

[frenkel]

I believe the seller can only be sure you sent him/her bitcoins, when he/she gave you an address nobody knows (a newly generated one). Proving an address belongs to you without sending money to it is difficult I guess.

[Stephen Gornick]

On the flip side of this, how can a buyer prove that he sent money to someone using a specific address?  And is there even a way to send money from a specific address you own?

This was discussed here:
  - http://forum.bitcoin.org/?topic=4411.0

[zef]

thanks for the responses. I was hoping there would be a better way.  I know if you run a server, there are commands you can send to it to receive a list of addresses, but I don't know if you can communicate with a server in like a "read only" mode so you wouldn't be able to command it to send coins. Something like that would be good, but it requires a little work on the users side to have a running server, give out an ip address ppl can connect to etc.  Not ideal, but I cant find any other methods that would achieve what i am looking for.