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trezor-firmware/docs/coins
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Tomas Susanka ccde69b5ff docs: coin paths modifications (yup, it wasn't final)
2018-08-29 17:22:31 +02:00
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bitcoin-path-check.svg docs: list of used derivation paths 2018-08-28 16:12:13 +02:00
README.md docs: coin paths modifications (yup, it wasn't final) 2018-08-29 17:22:31 +02:00

README.md

BIP-44 derivation paths

Each coin uses BIP-44 derivation path scheme. If the coin is UTXO-based the path should have all five parts, precisely as defined in BIP-32. If it is account-based we follow Stellar's SEP-0005 - paths have only three parts 44'/c'/a'. Unfortunately, lot of exceptions occur due to compatibility reasons.

List of used derivation paths

coin curve getPublicKey getAddress sign derivation note
Bitcoin secp256k 44'/0'/a' 44'/0'/a'/y/i 44'/0'/a'/y/i BIP-32 6
Ethereum secp256k 44'/60'/0' 44'/60'/0'/0/i 44'/60'/0'/0/i BIP-32 1
Ripple secp256k - 44'/144'/a'/0/0 44'/144'/a'/0/0 BIP-32 2
Cardano ed25519 44'/1815'/a' 44'/1815'/a'/0/i 44'/1815'/a'/0/i Cardano's own3
Stellar ed25519 - 44'/148'/a' 44'/148'/a' SLIP-0010
Lisk ed25519 44'/134'/a' 44'/134'/a' 44'/134'/a' SLIP-0010
NEM ed25519 - 44'/43'/a' 44'/43'/a' SLIP-0010 4
Monero ed25519 44'/128'/a'5 44'/128'/a' 44'/128'/a' SLIP-0010

Paths that do not conform to this table are allowed, but user needs to confirm a warning on Trezor. For getPublicKey we do not check if the path is followed by other non-hardened items (anyone can derive those anyway). This is beneficial for Ethereum and its MEW compatibility, which sends 44'/60'/0'/0 for getPublicKey.

Notes

  1. We believe this should be 44'/60'/a', because Ethereum is account-based, rather than UTXO-based. Unfortunately, lot of Ethereum tools (MEW, Metamask) do not use such scheme and set a = 0 and then iterate the address index i. Therefore for compatibility reasons we use the same scheme: 44'/60'/0'/0/i and only the i is being iterated.

  2. Similar to Ethereum this should be 44'/144'/a'. But for compatibility with other HW vendors we use 44'/144'/a'/0/0.

  3. Which allows non-hardened derivation on ed25519.

  4. NEM's path should be 44'/60'/a' as per SEP-0005, but we allow 44'/60'/a'/0'/0' as well for compatibility reasons with NanoWallet.

  5. Actually it is GetWatchKey for Monero.

  6. It is a bit more complicated for Bitcoin-like coins. The following diagram shows how path should be validated for Bitcoin-like coins:

bitcoin-path-check