> You can't put arbitrary data in a transaction, at least not very easily. No; it's very easy. Anyone sending Bitcoin can add arbitrary data in his transaction

> You can't put arbitrary data in a transaction, at least not very easily. No; it's very easy. Anyone sending Bitcoin can add arbitrary data in his transaction; no need to be a miner: https://en.bitcoin.it/wiki/Script#Transaction_with_a_message https://en.bitcoin.it/wiki/Script#Transaction_with_a_message