Include the fee explicitly in V6 transactions

[bitcartel]

Software should help users. When it comes to fee selection, it should be very hard to make mistakes. The current transparent fee computation (inherited from upstream) - input value less output value - is prone to user error. It is very easy to forget to add an output for a change address, make a calculation error, mix up units etc.

https://bitcointalk.org/index.php?topic=1818791.0 (Bitcoin network, March 8, 2017)

Please help, please, I sent a transaction with a $3000 fee by mistake, I can't afford to lose this much I am saving for college
Please help anyone https://blockchain.info/tx/4d45a14ee7320b97bafd550d60df1a1be524f3cfc8ca1ea6295279eeb7026aff What can I do?

[daira]

I thought there was an "absurdly high fee" safety check?

In any case, I'm in favour of fixed fees for both privacy and simplicity. Now that we've reduced the free transaction threshold, there's no reason not to just use a fixed fee of 0.0001 ZEC (currently about 0.3 US cents) for all transactions.

[zookozcash]

Related: zcash/zcash#2942

[radix42]

I don't want fixed fees..... I personally always double it on txns with a JoinSplit, for instance, and they get mined the next block.....leave it at the default, and not always

Just as a for instance.....and I do make frequent use of the inherited "sendtoaddress" command a lot too, and that cli command does seem to have sane defaults... so I am not sure what this is contemplating changing?

[radix42]

ah ok yeah now that I've read zcash/zcash#2942, THAT one makes sense

[nuttycom]

In the case that we create a V6 transaction format, we should change the fee behavior to make a consensus rule that the explicitly included fee matches the one calculated according to the current rules. (with @daira)

[teor2345]

In the case that we create a V6 transaction format, we should change the fee behavior to make a consensus rule that the explicitly included fee matches the one calculated according to the current rules. (with @daira)

This would also be very helpful for Zebra's parallel transaction verification. We could check explicit fees in transactions and blocks in parallel, and then check each transaction's inputs provide the specified fee in series.