Backing up master seed (0.13 and up)

[LookingIntoBTC]

Hi all,

I want an additional backup to the wallet.dat file. I was thinking of dumping the private key and storing it on paper somewhere safe, but I understand that it will be invalidated after 100 transactions?

Is there a way to get the master seed for the HD wallet? Will "dumpwallet" show me the seed?

Ideally I want something that I can enter directly into Bitcoin Core to regain access to my addresses.


Thanks in advance!

[1714793254]

1714793254

[1714793254]

1714793254

[1714793254]

1714793254

[1714793254]

1714793254

[1714793254]

1714793254

[1714793254]

1714793254

[mocacinno]

Hi all,

I want an additional backup to the wallet.dat file. I was thinking of dumping the private key and storing it on paper somewhere safe, but I understand that it will be invalidated after 100 transactions?

Is there a way to get the master seed for the HD wallet? Will "dumpwallet" show me the seed?

Ideally I want something that I can enter directly into Bitcoin Core to regain access to my addresses.


Thanks in advance!

you're talking about the 100 addresses gap limit. Since 0.13.0, this gap limit no longer exists (at least, if you created a new wallet with 0.13.0+... If you just opened your old wallet, there is no conversion from a non-HD to a HD wallet... This would be impossible).

Long story short: if you created a new wallet.dat with a version 0.13.0 or up, your wallet.dat can be backupped once, and it will not be invalidated after you create 100 new keys. There is no need to export the master private key.

[pepoaly007]

I think thats to hard to be an active

[ranochigo]

You do not need to backup after a 100 transactions. However, there is a specific behavior that you need to take note of. When encrypting your wallet, the wallet will save your previous addresses and generate a new seed to use from then on. When you encrypt your wallet, you do need to backup your wallet.dat again.

[LookingIntoBTC]

Hi all,

I want an additional backup to the wallet.dat file. I was thinking of dumping the private key and storing it on paper somewhere safe, but I understand that it will be invalidated after 100 transactions?

Is there a way to get the master seed for the HD wallet? Will "dumpwallet" show me the seed?

Ideally I want something that I can enter directly into Bitcoin Core to regain access to my addresses.


Thanks in advance!

you're talking about the 100 addresses gap limit. Since 0.13.0, this gap limit no longer exists (at least, if you created a new wallet with 0.13.0+... If you just opened your old wallet, there is no conversion from a non-HD to a HD wallet... This would be impossible).

Long story short: if you created a new wallet.dat with a version 0.13.0 or up, your wallet.dat can be backupped once, and it will not be invalidated after you create 100 new keys. There is no need to export the master private key.

I've made a new wallet.dat after 0.13.0, I've got that backed up. What I meant is an additional physical backup - for example, writing down the master seed on paper and storing it in a bank safe.

Initially I planned to do the following:


* Unlock wallet.dat file
* Run "dumpprivkey" with the corresponding address
* Save the resulting private key on paper, laminate it and store in a safe

But unless I'm mistaken, the private key will only be for the specific address I used, meaning it doesn't provide a long-time backup for all possible addresses derived from the master key. Is my understanding correct? Can I get a physical backup that will give me the same type of backup the wallet.dat file gives me?

[mocacinno]

I've made a new wallet.dat after 0.13.0, I've got that backed up. What I meant is an additional physical backup - for example, writing down the master seed on paper and storing it in a bank safe.

Initially I planned to do the following:


* Unlock wallet.dat file
* Run "dumpprivkey" with the corresponding address
* Save the resulting private key on paper, laminate it and store in a safe

But unless I'm mistaken, the private key will only be for the specific address I used, meaning it doesn't provide a long-time backup for all possible addresses derived from the master key. Is my understanding correct? Can I get a physical backup that will give me the same type of backup the wallet.dat file gives me?

If you wallet was encrypted, that's good, it means no new seed will be created. If you run dumpprivkey, one private key will indeed be dumped. If you save this pk, it can later be imported in a lot of different wallets.
You are correct tough... Your wallet will create new private keys, whith each his own publick key, and address. Each new pk won't be included in your laminated sheet.

It seems like the dev's are working on a method to export the master private key, from wich all other private keys can be derived using path m/0'/0'/k'
However, it seems this feature is not yet implemented (AFAIK).

My node is still running a non-HD wallet, so there is no way for me to test this out... If run on a clean pc, it should be relatively safe to test out the rpc command dumpwallet, and see if you're presented with a master private key... Feedback would be nice 

from https://bitcointalk.org/index.php?topic=1594650.0

Hierarchical Deterministic Key Generation

Newly created wallets will use hierarchical deterministic key generation
according to BIP32 (keypath m/0'/0'/k').
Existing wallets will still use traditional key generation.

Backups of HD wallets, regardless of when they have been created, can
therefore be used to re-generate all possible private keys, even the
ones which haven't already been generated during the time of thebackup.
Attention: Encrypting the wallet will create a new seed which requires
a new backup!

Wallet dumps (created using the dumpwallet RPC) will contain the deterministic
seed. This is expected to allow future versions to import the seed and all
associated funds, but this is not yet implemented.

HD key generation for new wallets can be disabled by -usehd=0. Keep in
mind that this flag only has affect on newly created wallets.
You can't disable HD key generation once you have created a HD wallet.

There is no distinction between internal (change) and external keys.

HD wallets are incompatible with older versions of Bitcoin Core.

Pull request, BIP 32