Producing a deterministic wallet

[jnano]

Storage media are not necessary or optimal for less than some thousands of characters.
Get an old manual typewriter and some high quality paper.

Nothing prevent you from using multiple backup media formats, including paper.

Surely digital media can store a few bytes just as well as a few GBs? Or even better, if you add redundancy.
It's at least useful for a full wallet backup, including metadata.

[1714916935]

1714916935

[1714916935]

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[nicknike]

With my continued quest to get some kind of paper back-up using Bitcoin-QT, does the following some feasible?

1) walletpassphrase YOURPASSPHRASE 10. This I beleive unlocks the wallet for 10 seconds.
2) During the 10 seconds, type dumpprivkey. Does this leave the bitcoins intact in Bitcoin-QT wallet? Does this dump a file showing all the private and public keys. If so, what is this file called and its extension?
3) Use importprivkey to import private keys back into Bitcoin-QT. If so, what is the procedure.
4) What does importmulti do? Is this relevant?
5) If this works, is there still a problem that if some bitcoins are sold, the 'change' bitcoins are still lost?
Thanks for your help.

[mocacinno]

I've tried to give feedback/answer the 5 questions:

1) walletpassphrase YOURPASSPHRASE 10. This I beleive unlocks the wallet for 10 seconds.

correct

2) During the 10 seconds, type dumpprivkey. Does this leave the bitcoins intact in Bitcoin-QT wallet? Does this dump a file showing all the private and public keys. If so, what is this file called and its extension?

Bitcoins aren't something physical, they are not stored on your pc. If you "own" bitcoins, it basically means you have access to the private key that can be used to create a signature for one or more unspent outputs that funded the address that was created by hashing the public key belonging to the private key in question.
In very simple wording: your bitcoins are just lines in blocks that are stored on thousands of computers. Importing or exporting private keys doesn't change anything (unless you use an unsafe procedure/PC and your private keys get exposed, in this case you might get robbed)
So, dumping the private key will not "destroy" your bitcoins.
dumpprivkey only dumps one private key to stdout. If you need to dump all private keys, you can use dumpwallet (dumpwallet actually takes a parameters in which you can define the file that will be used to dump all keys to)

3) Use importprivkey to import private keys back into Bitcoin-QT. If so, what is the procedure.

open the debug window => importprivkey --privatekey--
This procedure will rescan the blocks on your disk, importprivkey takes an optional argument that will avoid this rescan (if you want to)

4) What does importmulti do? Is this relevant?

I've never used this, but apparently it's used to import multiple private keys at once

5) If this works, is there still a problem that if some bitcoins are sold, the 'change' bitcoins are still lost?

I have a hard time understanding this question. IF you use a decent wallet, it will guide you trough the process of creating a transaction spending one or more of the unspent outputs controlled by you. A decent wallet will make sure it funds the address of whoever you're sending BTC to, and it will make sure the change is being used to fund a change address.
Only if you manually create a raw transaction, or if you use a newbie-unfriendly, bad, wallet, or if you start messing with options you don't understand, you might end up losing your funds.

[nicknike]

I've tried to give feedback/answer the 5 questions:

1) walletpassphrase YOURPASSPHRASE 10. This I beleive unlocks the wallet for 10 seconds.

correct

Ye-esss

2) During the 10 seconds, type dumpprivkey. Does this leave the bitcoins intact in Bitcoin-QT wallet? Does this dump a file showing all the private and public keys. If so, what is this file called and its extension?

Bitcoins aren't something physical, they are not stored on your pc. If you "own" bitcoins, it basically means you have access to the private key that can be used to create a signature for one or more unspent outputs that funded the address that was created by hashing the public key belonging to the private key in question.
In very simple wording: your bitcoins are just lines in blocks that are stored on thousands of computers. Importing or exporting private keys doesn't change anything (unless you use an unsafe procedure/PC and your private keys get exposed, in this case you might get robbed)
So, dumping the private key will not "destroy" your bitcoins.
dumpprivkey only dumps one private key to stdout. If you need to dump all private keys, you can use dumpwallet (dumpwallet actually takes a parameters in which you can define the file that will be used to dump all keys to)
OK, I understand that the Bitcoins are just computer code. So if I use dumpwallet, what file will be created? Can this be read as a text file? Is that how it is done? I have a number of bitcoins in Bitcoin-qt.
 Will these just have the one private key?

3) Use importprivkey to import private keys back into Bitcoin-QT. If so, what is the procedure.

open the debug window => importprivkey --privatekey--
This procedure will rescan the blocks on your disk, importprivkey takes an optional argument that will avoid this rescan (if you want to)
So do I copy the private key from the dumped text file and type

importprivkey --privatekey-- with the private key typed between --  and --? I know some of these symbols are instructions and not actually typed, but do I type the -- and --?.

4) What does importmulti do? Is this relevant?

I've never used this, but apparently it's used to import multiple private keys at once

5) If this works, is there still a problem that if some bitcoins are sold, the 'change' bitcoins are still lost?

I have a hard time understanding this question. IF you use a decent wallet, it will guide you trough the process of creating a transaction spending one or more of the unspent outputs controlled by you. A decent wallet will make sure it funds the address of whoever you're sending BTC to, and it will make sure the change is being used to fund a change address.
Only if you manually create a raw transaction, or if you use a newbie-unfriendly, bad, wallet, or if you start messing with options you don't understand, you might end up losing your funds.

So, I'm using Bitcoin-qt. If I import the private key, my bitcoin total will show-up, yes, and then I could, for example, send one bitcoin to my exchange and the remainder will still show in Bitcoin-qt for another time?

BTW, when typing-in instructions to the console page, I don't see an activation device, like a button. Is it ok to just highlight the code and hit Enter?
Also BTW, many, many thanks for the help. I don't understand all the terminology so have to take this to grass-roots level. You see, what is a 'raw transaction'? And 'by hashing the public key belonging to the private key in question@ is beyond my understanding.
Bitcoins seems to have terminology all of it's own from what I have seen all over the net.

[nicknike]

You don't get the BCH value when you sell BTC... you get the BCH by having had BTC on a private key when the fork happened... it doesn't matter what you do withe BTC "after" the fork has happened... the BCH will stay with the private key... you get your BCH by importing your BTC private key (or BTC wallet file) into a BCH wallet (like BitcoinABC or ElectronCash).

Many thanks.
So, say I sell 1 BTC. If I then use the wallet.dat file with BitcoinABC, will the equivalent BCH still be available? The only way I can see this working is if the BTC and BCH details are now both in the wallet.dat file. Is this the case? Presumably it would be a useful upgrade to Bitcoin-QT if it would show and allow transactions for both BTC and BCH.

[ranochigo]

OK, I understand that the Bitcoins are just computer code. So if I use dumpwallet, what file will be created? Can this be read as a text file? Is that how it is done? I have a number of bitcoins in Bitcoin-qt. Will these just have the one private key?

It can be opened using a text editor. If you're using a HD wallet, you will only get a string of alphanumerical characters, IIRC.

So do I copy the private key from the dumped text file and type

importprivkey --privatekey-- with the private key typed between --  and --? I know some of these symbols are instructions and not actually typed, but do I type the -- and --?.

No. importprivkey 5K 

Where 5K is your private key.

So, I'm using Bitcoin-qt. If I import the private key, my bitcoin total will show-up, yes, and then I could, for example, send one bitcoin to my exchange and the remainder will still show in Bitcoin-qt for another time?

Yes. You need to backup your wallet.dat though.

BTW, when typing-in instructions to the console page, I don't see an activation device, like a button. Is it ok to just highlight the code and hit Enter?
Also BTW, many, many thanks for the help. I don't understand all the terminology so have to take this to grass-roots level. You see, what is a 'raw transaction'? And 'by hashing the public key belonging to the private key in question@ is beyond my understanding.
Bitcoins seems to have terminology all of it's own from what I have seen all over the net.

Theres no button when you're using the console.

If you're just using Bitcoin for non-technical stuff, that isn't a must to learn.

So, say I sell 1 BTC. If I then use the wallet.dat file with BitcoinABC, will the equivalent BCH still be available?

Yes. If you do it after the fork and the 1BTC transaction was already in your wallet before the fork.

The only way I can see this working is if the BTC and BCH details are now both in the wallet.dat file. Is this the case? Presumably it would be a useful upgrade to Bitcoin-QT if it would show and allow transactions for both BTC and BCH.

For the same BTC and BCH address, they have the same private key. There's no separate details, its just a private key.

It won't be. Bitcoin Core is catered to only Bitcoin. Bitcoin Cash is a different alt-coin altogether.

[HCP]

So, say I sell 1 BTC. If I then use the wallet.dat file with BitcoinABC, will the equivalent BCH still be available?

Yes. Like I said... it doesn't matter what you do with BTC AFTER the fork... the BCH remains associated with the the private key/address and will only move when a properly created/signed BCH transaction is broadcast and confirmed on the BCH blockchain.

The only way I can see this working is if the BTC and BCH details are now both in the wallet.dat file. Is this the case?

No. The wallet really just contains the private keys (technically it does contain some transaction information, but this can be altered/removed). The important data are the private keys. Everything else can be retrieved from the Blockchain.

Presumably it would be a useful upgrade to Bitcoin-QT if it would show and allow transactions for both BTC and BCH.

No. That would be a mess. It is "slow" enough now having to maintain/scan one blockchain... having the same app have to download/process/validate TWO 150+Gig blockchains would be terrible.

Besides, you'll find that the BCH version (Bitcoin ABC)... is also called Bitcoin-QT The reasons for this are mostly political.