Bitcoin Forum

Bitcoin => Bitcoin Wallet for Android => Topic started by: d4n13 on December 23, 2017, 04:11:55 AM



Title: Import Android wallet to Trezor [SOLVED]
Post by: d4n13 on December 23, 2017, 04:11:55 AM
Anyone try this.... thought it might be fun.

So I saw in decrypt threads (https://bitcointalk.org/index.php?topic=1997031.0) that someone was able to extract the BIP32 key and derivation path.  Since both of these can be loaded into a Trezor, has anyone tried this to see if they get the proper key data?  I plan to... but not till next year.  Too much to do right now.  Maybe we can get a thread started to try to figure out the gotchas before I dig to deep.

Thx


Title: Re: Import Android wallet to Trezor
Post by: HCP on December 23, 2017, 12:44:31 PM
I was under the impression that you cannot use a "custom derivation path" in a Trezor... for BTC it will always use m/44'/0'/0' as it is a BIP44 compatible hardware wallet.

Your seed will still likely work, as it is still a BIP39 seed...  but without the ability to specify the "non-BIP44" derivation path that Android Bitcoin Wallet uses, you will NOT be able to seed the same addresses as generated by the Android app.


Title: Re: Import Android wallet to Trezor
Post by: d4n13 on December 23, 2017, 04:13:31 PM
trezorctl allows any derivation


Title: Re: Import Android wallet to Trezor
Post by: HCP on December 27, 2017, 12:07:32 AM
Unfortunately, I don't think it will work. :-\

The "load_device" command will allow you to load the mnemonic or xprv...
Code:
Usage: trezorctl load_device [OPTIONS]

  Load custom configuration to the device.

Options:
  -m, --mnemonic TEXT
  -e, --expand
  -x, --xprv TEXT
  -p, --pin TEXT
  -r, --passphrase-protection
  -l, --label TEXT
  -i, --ignore-checksum
  -s, --slip0014
  --help                       Show this message and exit.

but there is no command that you can issue that will cough up private keys etc... The best I can see is get_address, command which will return an address for a specified coin type and derivation path, but I don't see a way to get the private key data... :(
Code:
Usage: trezorctl get_address [OPTIONS]

  Get address for specified path.

Options:
  -c, --coin TEXT
  -n, --address TEXT              BIP-32 path, e.g. m/44'/0'/0'/0/0
                                  [required]
  -t, --script-type [address|segwit|p2shsegwit]
  -d, --show-display
  --help                          Show this message and exit.

Only the "pubkey" using get_public_node:
Code:
Usage: trezorctl get_public_node [OPTIONS]

  Get public node of given path.

Options:
  -c, --coin TEXT
  -n, --address TEXT  BIP-32 path, e.g. m/44'/0'/0'  [required]
  -e, --curve TEXT
  -d, --show-display
  --help              Show this message and exit.

which returns the following:
Code:
node.public_key: 03edc955f8d1d49d6fdc11c183063f58320c969c7b5d7e6f5705523b9ef19bbd24
node.depth: 2
node.chain_code: 7551a39e04e7fa60643409a92f5135240673c0a2ddf4970bd14ee22f6a953945
node.child_num: 0
node.fingerprint: df26a6b1
xpub: xpub6BQmKf6WWF63QP6zTEZF4cmbdfS7ziZWh3NECMeV69cFhD2u3aMZPb9ptVy8g1zx9WYwRMNzkxDs7s2vHiXyaGtagcy26XSXyk5vXC2838q


Title: Re: Import Android wallet to Trezor
Post by: d4n13 on December 27, 2017, 10:04:41 PM
Yep... totally works...  Here's the howto.

Required tools:
  • The wallet backup file
  • A trezor your willing to wipe
  • A laptop with Python

Walk through

Code:
pip install git+git://github.com/trezor/python-trezor.git@888b6f9
pip install protobuf pylibscrypt
git clone https://github.com/gurnec/decrypt_bitcoinj_seed.git
cd decrypt_bitcoinj_seed
git checkout a9e6ae3
git checkout -b commit_a9e6ae3
pythonw decrypt_bitcoinj_seed.pyw
<answer questions>
<copy mnemonic>
trezorctl wipe_device
trezorctl load_device -m "<aquired mnemonic from decrypt_bitcoinj_seed.pyw>"
trezorctl get_address -n "m/0'/0/0"

Few things to note
  • The last step above should match the first receiving address you android wallet generated.
  • Decrypting a wallet exposes the keys to memory and a host of other attack vectors.  Know the risks, or try this on an empty wallet.
  • Wiping a trezor will force you to recover it through recovery.  If you forgot your trezor mnemonic, things will end poorly.
  • Trezor SW uses a different derivation path than this android wallet.  You will need to use trezor python tools or API libraries to do anything useful.
  • The above checks out the specific revisions on these repos as of Dec 24th (approx).  If you want new code, be aware.



Title: Re: Import Android wallet to Trezor [SOLVED]
Post by: HCP on December 28, 2017, 08:45:40 AM
Oh... right, so you weren't actually after the key data... you just wanted to load a BIP39 seed with a custom derivation path and then use that in conjuction with your Trezor on an ongoing basis...

sorry, got confused when you said:
... Since both of these can be loaded into a Trezor, has anyone tried this to see if they get the proper key data?

Given that the "sign_transaction" command will also accept the m/0'/0 address argument, there should be no issues making your Trezor work like this... except of course the fact that you need to use trezorctl to do anything with it :P

Still, nice to know that it can be done... that's another plus for Trezor!


Title: Re: Import Android wallet to Trezor [SOLVED]
Post by: d4n13 on December 28, 2017, 08:55:43 PM
Oh... right, so you weren't actually after the key data...

Sure I was.  I wanted the Trezor to obtain the proper key data.  Never thought the Trezor would give that data to me.

Reason I went on the BIP39 route instead of the BIP32 route was the availability of decrypt_bitcoinj_seed.  I have a hate in my heart for Java, and there is a special spot in heaven for those that labor through it.  A python / nodejs solution was much more to my liking.

If you wanted to do the BIP32 route, I believe that the BIP32 xpriv is extractable from the protobuf as well.  I generated some random BIP32 nodes and verified that Trezor accepted them just fine.