The question is basically in the title. Can I (or it is possible to) extract the chain code from a ledger nano s device? It doesn't have to be the Master Chain Code. Any of them will do.
Yes. You can get the public key, chaincode, and address for any derivation path.
If you use the btchip-python library, you can use the getWalletPublicKey() method to retrieve a dictionary containing all three of those things.
answered Feb 12 '19 at 18:21
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Hey, thanks for the response. How to I get python to interact with the ledger device? – Ppeters62 Feb 12 '19 at 19:34
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You need to use
getDonglefrom github.com/LedgerHQ/btchip-python/blob/master/btchip/… to get the device object to do the calls with. Alternatively you can use the HWI project (github.com/bitcoin-core/HWI) to get an xpub from your Ledger and extract the chaincode from that. HWI is a python library and command line tool to do stuff with hardware wallets. – Andrew Chow♦ Feb 12 '19 at 21:11
Extracting BIP 32/39/44 chain code is agnostic as to whether a Ledger device or Trezor device is used. Remember the chain code is based upon open standards, specifally see https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki#serialization-format.
Here is how chain code can be found for the Bitcoin path m/44'/0'/0'/0 for the example at https://github.com/libbitcoin/libbitcoin-system/wiki/Altcoin-Version-Mappings#7-bitcoin-btc-bip-3944-technology-examples:
This is the level the chain code was determined for below:
% echo "radar blur cabbage chef fix engine embark joy scheme fiction master release" | bx mnemonic-to-seed | bx hd-new | bx hd-private -d -i 44 | bx hd-private -d -i 0 | bx hd-private -d -i 0 | bx hd-private -i 0 | bx base58-decode | cut -c 9-10
04
This is the index the chain code was determined for below:
% echo "radar blur cabbage chef fix engine embark joy scheme fiction master release" | bx mnemonic-to-seed | bx hd-new | bx hd-private -d -i 44 | bx hd-private -d -i 0 | bx hd-private -d -i 0 | bx hd-private -i 0 | bx base58-decode | cut -c 19-26
00000000
This is the chain code for the particular level and index:
% echo "radar blur cabbage chef fix engine embark joy scheme fiction master release" | bx mnemonic-to-seed | bx hd-new | bx hd-private -d -i 44 | bx hd-private -d -i 0 | bx hd-private -d -i 0 | bx hd-private -i 0 | bx base58-decode | cut -c 27-90
6fbe96de86322b27a540572e2777562f55fb9810327917f9dd1163592952272a
This is the associated secp256k1 private key:
% echo "radar blur cabbage chef fix engine embark joy scheme fiction master release" | bx mnemonic-to-seed | bx hd-new | bx hd-private -d -i 44 | bx hd-private -d -i 0 | bx hd-private -d -i 0 | bx hd-private -i 0 | bx base58-decode | cut -c 93-156
c227b3ba34eecfee2830b06bef3b35d5a88d4f6a9c5f34bd3d4e465e6c3ead1f
