66 lines
2.4 KiB
Markdown
66 lines
2.4 KiB
Markdown
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# Coldcard Hardware Wallet Plugin
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## Just the glue please
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This code connects the public USB API and Electrum. Leverages all
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the good work that's been done by the Electrum team to support
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hardware wallets.
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## Background
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The Coldcard has a larger screen (128x64) and a number pad. For
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this reason, all PIN code entry is done directly on the device.
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Coldcard does not appear on the USB bus until unlocked with appropriate
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PIN. Initial setup, and seed generation must be done offline.
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Coldcard uses an emerging standard for unsigned tranasctions:
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PSBT = Partially Signed Bitcoin Transaction = BIP174
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However, this spec is still under heavy discussion and in flux. At
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this point, the PSBT files generated will only be compatible with
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Coldcard.
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The Coldcard can be used 100% offline: it can generate a skeleton
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Electrum wallet and save it to MicroSD card. Transport that file
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to Electrum and it will fetch history, blockchain details and then
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operate in "unpaired" mode.
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Spending transactions can be saved to MicroSD using the "Export PSBT"
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button on the transaction preview dialog (when this plugin is
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owner of the wallet). That PSBT can be signed on the Coldcard
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(again using MicroSD both ways). The result is a ready-to-transmit
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bitcoin transaction, which can be transmitted using Tools > Load
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Transaction > From File in Electrum or really any tool.
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<https://coldcardwallet.com>
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## TODO Items
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- No effort yet to support translations or languages other than English, sorry.
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- Coldcard PSBT format is not likely to be compatible with other devices, because the BIP174 is still in flux.
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- Segwit support not 100% complete: can pay to them, but cannot setup wallet to receive them.
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- Limited support for segwit wrapped in P2SH.
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- Someday we could support multisig hardware wallets based on PSBT where each participant
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is using different devices/systems for signing, however, that belongs in an independant
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plugin that is PSBT focused and might not require a Coldcard to be present.
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### Ctags
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- I find this command useful (at top level) ... but I'm a VIM user.
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ctags -f .tags electrum `find . -name ENV -prune -o -name \*.py`
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### Working with latest ckcc-protocol
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- at top level, do this:
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pip install -e git+ssh://git@github.com/Coldcard/ckcc-protocol.git#egg=ckcc-protocol
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- but you'll need the https version of that, not ssh like I can.
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- also a branch name would be good in there
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- do `pip uninstall ckcc` first
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- see <https://stackoverflow.com/questions/4830856>
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