Nevertheless, if grandchild key pair 1 accommodates 1 BTC, and grandchild key pair 2 accommodates 2 BTC, might I ship the three BTC complete as a single transaction?
Sure, however not in the best way you describe it.
Bitcoin, on the protocol stage, doesn’t “belong” to a key. That’s, there is no such thing as a stability per tackle or per key as an idea.
As a substitute, consider them as cash. Each time you receives a commission, you obtain a separate new “coin”. Every coin has just a little program (the locking script) that determines who’s allowed to spend it. In apply, your cash are ones with a locking script that requires a signature with a key you could have.
The protocol permits creating transactions that spend a number of cash without delay. It doesn’t matter whether or not these cash all have the identical tackle, or totally different addresses derived from the identical grasp key, or even when they’ve utterly unrelated addresses totally. They’re simply a number of cash, and every coin individually requires a signature.
actually, nothing prevents a number of folks from establishing a single transaction that spends a number of cash owned by totally different folks in the identical transaction. That is known as a CoinJoin transaction.
In that case, would this seem on-chain to depart from the kid key pair tackle from which each are derived?
All HD wallets do is change the best way a person pockets derive their keys. Different nodes or events on the community have no idea or care the keys are constructed in a associated method. So long as they have no idea the grasp public key, your keys are indistinguishable from random keys. The one factor seen on chain is that the transaction spent cash that had been beforehand despatched to distinct addresses, however that is the case for nearly all transactions on the community.
If the grasp personal key was in chilly storage, however one of many baby personal keys was not, might the pockets be outlined as a chilly pockets?
This isn’t doable with non-hardened keys. Given a baby personal key and the grasp public key, you’ll be able to compute the grasp personal key, and from that, all different baby personal keys.
Thus, you state of affairs is equal to the non-cold system gaining access to all personal keys, and the entire setup could be very a lot not chilly.
With hardened keys, figuring out the kid personal key doesn’t reveal the grasp personal key, however you lose the benefit of with the ability to compute baby public keys with out entry to the grasp personal key.
in both case, I might not name this a chilly setup. I might reserve that time period for setups the place no cash are ever on a web-based system.