Personal Keys Relationship in HD Wallets

1. What is the relationship between the primary pkey/addr (the one with hdkeypath: m/0'/0'/0 and the third one m/0'/0'/2?

They’re derived from the identical father or mother key. Aside from that, there is no such thing as a relation.

Does the primary key/addr is the grasp (key) who can recuperate all later keys generated within the pockets.

No. They’re each little one keys of the important thing at m/0'/0'. The precise grasp personal key (the important thing at m) shouldn’t be exportable. There’s a HD seed (which is used to generate the grasp personal key at m), however that is solely exportable via the dumpwallet RPC.

2. I solely backup the personal key of m/0'/0'/2, and eliminated the entire pockets (the .dat file). Is there a danger of this technique? Since I solely select to make use of this key/addr to obtain and retailer BTC.

Do not do this, you’ll lose cash. Whenever you ship Bitcoin, Bitcoin Core will generate new change addresses and ship any change there. These change addresses have totally different personal keys. With out them, you’ll lose cash.

Moreover, by reusing the identical handle, you’re considerably hurting your privateness. Through the use of the identical handle again and again, anybody you transact with will understand how a lot cash you could have in your pockets and be capable to see your entire incoming and outgoing transactions. This permits anybody to trace your spending habits.

3. I later create a brand new pockets and restore this m/0'/0'/2 key with command importprivkey. and ship some BTC to different individuals, and located it generate a CHANGE addr, so I additionally backup this new addr’s personal key too. Since I primarily use this m/0'/0'/2 to retailer long run BTC, and won’t use it to make lots transactions. So I preserve the privatekey of m/0'/0'/2, and preserve backups priv keys of change addresses it generated, then drop all pockets recordsdata. Is that this technique sufficient to revive all my balances in a futher day.

Bitcoin Core always generates new change addresses. The one time you overlook signifies that you’ll lose cash. In case you unintentionally request a brand new handle and use it, you’ll lose cash.

Generally, backing up particular person personal keys shouldn’t be really helpful. It’s best to again up the complete pockets.dat file itself. There isn’t a must export every key individually and again it up in that approach. That may be a surefire solution to lose cash in some unspecified time in the future sooner or later.

4. Can the personal key of m/0'/0'/2 be used to recuperate the change addresses’ personal keys? (What’s the grasp seed of HD pockets, it’s the personal key of m/0'/0'/0?)

No. The change addresses are unrelated. You would want to have the HD seed talked about beforehand to be able to derive them.