On 19 August 2015 at 13:44, Jameson Lopp <jameson.l...@gmail.com> wrote: > It's possible to check that a transaction is cryptographically valid without > having any blockchain data available; are you referring to a different type > of validation?
It seems laborious to enumerate all the validations that are performed on a transaction before it can be mined into a block, but for starters we need to check it isn't a double-spend, and that its signatures satisfy the outputs' pubkeys. > If you're running an SPV node that is listening to full nodes on the > network, you can request an unconfirmed transaction from connected peers > after receiving the inventory message they send - that's how unconfirmed > transactions propagate through the node network. This is not 100% proof that > the transaction is valid for inclusion in the blockchain, but it's a very > good indicator. If you as an SPV node are waiting for unconfirmed transactions to be relayed to you, you are going to have a slow start in mining those transactions, decreasing the likelihood of receiving the mining reward. Nodes should accept the first POW for a transaction and discard any subsequent ones received. _______________________________________________ bitcoin-dev mailing list bitcoin-dev@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
