I had started writing this post when diving online I have come across several pages of bitcoiners who had already written about the generation of keys using Ian Coleman’s BIP39 tool plus the Tails system, so I will limit myself to putting the links already specify the steps roughly.
Before providing funds to our hardware wallet Coldcard (CC) It is important to make sure that in the future whatever happens we will be able to recover them.
Over the years many situations can arise whereby we find ourselves in the position of having to recover these funds without having the hardware wallet (hww), such as losing it or it being damaged and not being manufactured anymore, either because that model does not exist or because the company has closed. To this day we do not know which companies will exist and which will not exist in 10 years, and although it was still alive, technology evolves very quickly and within a few years devices that are now in common use may not be available, such as microSD memory cards, microUSB connectors, internal battery…
Therefore it is vitally important to verify that we are going to be able to access the private keys that our hww handles. In this post we will test to recover these private keys from the CC addresses in other wallets from the generated seed and the passphrase that we have put.
There is documentation on this on the Coldcard website on how to carry out this operation, but I think that this is well worth a practical exercise to verify that this is the case. There is also apage walletsrecovery. where they give very valuable information about the compatibility between the different wallets.
Turn on the Coldcard, for this we connect it to an external USB charger or an adapter connected to a socket, never charge it with the USB connector of the computer we must keep the Coldcard always offline.
Put the prepin and the pin, you have to write it down because the device will request it whenever you turn it on. Do not save them on any digital medium or on the Internet, you have to minimize the risks.
Updating the firmware is optional but recommended, we will not go into it.
Create the wallet
Option: New Wallet
Add the passphrase and write it down because it is not saved in the hww. Important, it must be entered every time the Coldcard is started and you want to operate with these addresses.
Option: Passphrase → Edit Phrase → APPLY → OK
When you start the HWW it will not warn you that you have to enter it and the menus they have do not help but if you forget to enter it you will end up operating with other different Bitcoin addresses.
Option: Passphrase → A very long explanatory text but that is important because it indicates the problem of not entering it → Edit Phrase, It is not the best text for this option since what you have to do is enter your Passphrase and not edit it and then → APPLY → OK
When choosing the passphrase it is important that it is very difficult to discover on this page “Can BIP-39 passphrase be cracked?” they tell you how secure your password is.
Visualize your identity.
Option: Advanced → View Identity to ensure that everything has been done correctly, we can check the fingerprint and that the text “BIP30 passphrase is in effect” appears to ensure that we are working with our passphrase.
Enter a microSD and export master public key (xpub) for the Electrum wallets and Wasabi which is where in the future we could import them.