# Gavin Andresen
# 2011-03-12 20:27:32
# https://bitcointalk.org/index.php?topic=4411.msg64632#msg64632

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 @p{brk}
Something like this is possible (I've been thinking about doing it, although I have higher priority things on my TODO list): @p{par}


@p{(li}Sophisticated user runs a tool on her computer that, giving the bitcoin address payment was sent to and "here's a description of me or what I paid for" string.  Tool looks in the wallet.dat and figure out which keypair(s) were used to pay.  Then it does some openssl magic and exports a file that contains the string, the public keys and ECDSA signatures using the private keys of the "description of me or what I paid for" string.@p{li)}

@p{(li}Sophisticated user uploads that file to a "Prove I Paid" website, which checks the signatures and adds info to the database.@p{li)}

@p{(li}Unsophisticated user goes to website and pastes the receiving address.  The public key corresponding to that address is looked up, and all the "here's a description of me or what I paid for" strings for that public key are shown.@p{li)}
 @p{brk}
bitcointools+openssl (see grondilu's thread about "a shell-script implementation of bitcoin) are enough to do all all the public/private key, file-creation, and signature generation/checking stuff. @p{brk}