Bitcoin Miners Are Submitting Coinbase Rewards From Other Blockchains Onto Bitcoin
How is This Happening?
As stated above, this is occurring via a process called ‘merged mining’, through which certain large mining pools have been able to submit blocks from other chains to the Bitcoin blockchain in order to effectively claim the block reward without completing the requisite amount of work.
The explanation of this requires a technical knowledge of Bitcoin down to the mechanisms that underpin how it works.
Long story, short - UTXO verification rules apply to every aspect of Bitcoin but coinbase rewards. Coinbase rewards are newly generated transactions, the typical verification process (i.e., checking to ensure that the spent outputs match up with the inputs & tracking the history of the UTXO through to the actual coinbase itself).
These transactions also take advantage of the signature separating framework of SegWit.
Using AuxPow, such a process of ‘gaming’ Bitcoin has been taking place using altcoins, ‘Devcoin’ and others.
Example of This Taking Place
Here is an example one of the ‘merged mined’ transactions that can be correlated directly to Bitcoin: https://chainz.cryptoid.info/dvc/block.dws?389160.htm
Below are photos displaying the details of the raw block:
The TX ID in the block header (depicted above) for ‘Devcoin’ can also be found on the Bitcoin blockchain itself (for the coinbase transaction of block height 593182)
Refers to this Bitcoin transaction (Coinbase TX).
SegWit TX though - nonstandard.
Didn’t even know that Coinbase TXs could be SW until I saw these kinds of TX.
TX ID = 541490f82e7903e474d5b2f04c8ddb4ed878a9783fe2175e1eb1a546567ed224
In addition, the other relevant transaction/block header details for the coinbase transaction on Bitcoin’s blockchain that were mentioned before can be found in the Devcoin block header as well:
What’s even more unique about the transaction above is that it is a ‘merge mined’ SegWit (Segregated Witness) transaction done via ‘AuxPoW’.
Words like “commitment hash” exist in reference to SW conventions.
More Information on Merged Mining + SegWit Specifications
This process is rather vague, hasn’t really been discussed since Namecoin was popular.
SegWit is also poorly understood
Here are some reference links:
Bitcoin Wiki Merged Mining Specification = https://en.bitcoin.it/wiki/Merged_mining_specification
BIP 143 (TX sig verification for version 0 witness program) = https://github.com/bitcoin/bips/blob/master/bip-0143.mediawiki
This is what the TX information looks like for the first merged mined block (on Namecoin, notably)
Looking Back at Devcoin (Very Strange Occurrence)
If we go back to the block header data for the block that was isolated for ‘Devcoin’, the following can be observed:
Above are the isolated UNIX timestamps for both Bitcoin and Devcoin in the Devcoin block header.
Parent Chain = Bitcoin
Child Chain = Devcoin
Parent Chain (Bitcoin) = 1567583091
Child Chain (Devcoin) = 1567582925
Converting the UNIX Timestamps to MM/DD/YY 00:00 Format
Below is the converted UNIX timestamp for the parent chain (Bitcoin):
Below is the converted UNIX timestamp for the child chain (Devcoin):
Notably the timestamp for Devcoin comes a full two minutes before Bitcoin’s, yet it still contains all of the relevant information for Bitcoin within the timestamp (including the actual timestamp of the next Bitcoin block).
How is This Possible?
The author(s) of this post have absolutely no clue, but it is something that should be clarified by the lead developers of Bitcoin (as well as Devcoin), especially in light of the relative lack of documentation surrounding ‘merged mining’.