bip 70
https://github.com/bitcoin/bips/blob/master/bip-0070.mediawiki
Now i understand: http://bitcoin.stackexchange.com/questions/24423/transaction-refund-address/24450#24450
https://github.com/bitcoin/bips/blob/master/bip-0070.mediawiki
Now i understand: http://bitcoin.stackexchange.com/questions/24423/transaction-refund-address/24450#24450