Derivation Paths and "Accounts"
(new in v3.1.1)
When exporting files for Bitcoin Core or Electrum, you may now press "1" at the confirmation screen, and then enter an arbitrary "account number" on the Coldcard. That account number is put as the last hardened component of the derivation path for the wallet's keys.
In this example, if a segwit-style wallet was made, the full derivation path of the first address (non-change) would be:
615' in the the path. By default, account number is zero.
Dump Summary File
The "Dump Summary" command can be found here: Advanced > MicroSD > Dump Summary
This command saves a text file to the MicroSD with a summary of the public details of your wallet. For example, this gives the XPUB (extended public key) that you might need to import into other wallet software to track balance.
By design, this output includes the effects of your BIP39 passphrase but does not indicate it is being used.
Here is an example of the file produced by Coldcard.
There are sections with derived (public) keys for a number of different wallet systems, and the first five payment addresses derived for each is shown:
- Bitcoin Core
- Bitcoin Core (Segregated Witness, P2PKH)
- Electrum (not BIP44)
- BIP44 / Electrum
- BIP49 (P2WPKH-nested-in-P2SH)
- BIP84 (Native Segwit P2PKH)
Although the subkey derivation will be correct, and we have researched the BIP32 derivation paths in use by these popular systems, we make no guarantees about what they are using at present, and some are configurable.
Do not make deposits to these payment addresses without confirming they match the wallet in question, and in general, please only use addresses produced by the wallet which will be responsible for tracking the UTXO on the blockchain. These can be verified using the "Address Explorer", found on the Advanced menu.