Ninjastic
PostEdited versionsQuotes to this post
Post
Topic
Board Bitcoin Technical Support
Re: SegWit change address becomes legacy???
by
columbo
on 15/11/2017, 17:21:44 UTC
Quote from: cellard on November 15, 2017, 05:13:26 PM
Quote from: columbo on November 15, 2017, 04:39:26 PM
Quote from: cellard on November 15, 2017, 04:31:03 PM
Quote from: columbo on November 14, 2017, 06:44:34 PM
What do you think about this solution?
In my case, after a transaction from segwit addresses I ended up with my entire balance on one legacy address.
So, what if before each spending, I check the balance of the wallet (in my case only one address) and calculate the change amount before payment is made.
So, for example: if my balance is 0.55 and I need to send 0.25 to somebody, the change will be 0.30 (minus fee).
Now, I can easily include in sendmany a new (or existing) segwit address I generate and make sure the fee is deducted only from the new segwit address. This way, I will end up with 0.30 minus the sending fee in a new segwit address. And next time, when I send out funds, I always do this, so I will always end up with my balance on one segwit address.

Is there anything wrong with my assumption?

How do you specify what address in sendmany will be used as a miner's fee?

Code:
sendmany {address:amount,...} [minconf=1] [comment]

The point of sendmany was to allow several recipients (to send to different addresses at once from a single input) but I dont see where it lets you specify what address is going to be used as a fee.

I would be sure to know what im doing before doing anything of this nature.

sendmany has the option to select which receiving address will pay the fee. So, if I treat my change / segwit address as one of the recipients and specify that the fee is deducted only from this new change / segwit address than this address will receive everything back (my starting balance on original segwit account minus all payments need to be made) minus the fee.

https://chainquery.com/bitcoin-api/sendmany

Parameter #1—from account
Parameter #2—the addresses and amounts to pay
Parameter #3—minimum confirmations
Parameter #4—a comment
Parameter #5-subtractfeefromamount is missing from the bitcoin RPC GitHub Issue #6500
Result—a TXID of the sent transaction

But where are you choosing what address you want to use to recieve the change of the address? You may be able to choose paramater 5 (which is not substractfeefromamount but subtractfeefrom  followed with the address):


Code:
5. subtractfeefrom         (array, optional) A json array with addresses.
                           The fee will be equally deducted from the amount of each selected address.
                           Those recipients will receive less bitcoins than you enter in their corresponding amount field.
                           If no addresses are specified here, the sender pays the fee.
    [
      "address"          (string) Subtract fee from this address
      ,...
    ]

But I still don't see any command that lets you specify what address you want to receive the change at?

To a new segwit address I create. So, it needs more steps:
1. Check your balance ($balance).
2. Calculate the real amount you need to send to different receivers ($amounttosend).
3. Calculate how much is the rest ($rest = $balance - $amounttosend).
4. Create a new segwit address (bitcoin-cli addwitnessaddress 1....) $segwitchangeaddress
5. Create the sendmany command with all the addresses and amounts where you need to send + add another recipient ($segwitchangeaddress) with the $rest as amount and select to pay the fees only by this address.

This way, you always spend ALL your output but you can make sure that the change / rest is coming back to a segwit address, not a legacy address. Does that make sense?