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Somebody wants to do a deal for a bitcoin transaction but when proof of the coins is required they say that the coins will not show up on blockchain.info as they were "mined coins".
Is this really true? Will mined coins really not show up on blockchain.info for the address' balance?
If that is the case how can proof of funds of bitcoins be seen before the deal goes through?
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They DO show up in the blockchain. The block reward(new mined coins) is sent to the miners address who has found a block via the coinbase transaction.
The coinbase transaction can be viewed and is found as the first transaction in every block.
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correction Nov 15: There is in each block a coinbase transaction and it"s always the first transaction.
The mined coins show up and the balance can be seen in the explorers (miners reward plus fees). Not necessarily it's in the first transaction of a block and not necessarily a block needs to contain a miners reward, but in most cases it is there and it's the first transaction. You can recognize the miners reward coinbase transaction because the explorer shows only for this one no input transactions where the coins derive from.
Could you please elaborate what you mean with " Not necessarily it's in the first transaction of a block"? Are you talking about payouts from a mining pool to the pool contributors or something? Because the coinbase transaction is required and it has to be the first transaction in the block. – Murch – 2019-11-13T20:21:50.937
There are blocks where the coinbase transaction is not the first transaction in the block. I realised because programs stopped because of this and I needed to modify. As well for a valid block it's not mandatory to have a coinbase reward at all or the miner can reduce the reward, only above the limit would make the block invalid. Here an example block with a coinbase reward of 0: Block 501726 (transaction 9bf8853b3a823bbfa1e54017ae11a9e1f4d08a854dcce9f24e08114f2c921182 ) – tempo – 2019-11-13T22:44:48.003
Need to partially correct myself. A coinbase transaction is mandatory in a valid block. The accepted value is maximal 50 BTC for the first 210,000 blocks and then halving every 210,000 blocks (less is not making the block invalid, even not 0 BTC). It can be sent to one or more addresses as long as the total value isn"t higher than the coinbase + the fees. It can be spend after 100 confirmations except the genesis 50 BTC which are unspendable. At least in the early protocol versions it was possible to put the coinbase transacition not on the top of the outputs. – tempo – 2019-11-13T23:55:06.980
huh, never heard about that before. I posted a new question about that here: https://bitcoin.stackexchange.com/q/91683/5406
1Do you mean that Coinbase transactions can have multiple outputs or are you talking about a different coin? Otherwise, it seems that Coinbase transactions have always been required to be the first transaction in a block (see question I posted above)' – Murch – 2019-11-14T17:55:32.077
The coinbase transaction can have of course multiple outputs. I talk about Bitcoin BTC. I'm trying to find the script which stopped at a block where the coinbase wasn't the first transaction. Will report back as soon as I find it or alternatively if my memory is wrong and I mixed up with something else... . – tempo – 2019-11-14T21:26:55.627
1Found my mistake. I once loaded all transactions into a separate database and had an error which mixed up the order of some transactions in their blocks .That led me to the wrong assumption that a coinbase reward transaction isn"t necessarily the first transcation. As double check I scanned tonight all 600k first transactions of the blocks and indeed they are all flagged as 'coinbase'. Apologies for confusing you! – tempo – 2019-11-15T10:10:53.007
Okay, thanks for your effort and checking! – Murch – 2019-11-15T14:11:01.853
Thank you. So to clarify, if the bitcoin seller claims to have bitcoins but their address provided shows as having zero bitcoins on blockchain.info, then it is likely that the address does not actually hold the amount of bitcoins they claim it does, as even if they had mined the coins that would show up on their balance on blockchain.info? – John Murphy – 2018-03-13T09:25:58.367
Thats right. Although I am not too sure if blockchain.info shows unconfirmed balances. – fihdi – 2018-03-14T16:54:19.777