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trezor-firmware/docs/misc/coins-bip44-paths.md

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# 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.
Keys are derived according to [SLIP-10], which is a superset of the BIP-32 derivation
algorithm, extended to work on other curves.
[bip-44]: https://github.com/bitcoin/bips/blob/master/bip-0044.mediawiki
[bip-32]: https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki
[sep-0005]: https://github.com/stellar/stellar-protocol/blob/master/ecosystem/sep-0005.md
[slip-10]: https://github.com/satoshilabs/slips/blob/master/slip-0010.md
## List of used derivation paths
| coin | curve | path | public node | note |
| -------- | --------- | ------------------ | ----------- | -------------- |
| Bitcoin | secp256k1 | `44'/c'/a'/y/i` | yes | [1](#Bitcoin) |
| Ethereum | secp256k1 | `44'/c'/0'/0/a` | yes | [2](#Ethereum) |
| Ethereum | secp256k1 | `44'/c'/0'/a` | yes | [2](#Ethereum) |
| Ripple | secp256k1 | `44'/144'/a'/0/0` | | [3](#Ripple) |
| EOS | secp256k1 | `44'/194'/a'/0/0` | | [3](#Ripple) |
| Binance | secp256k1 | `44'/714'/a'/0/0` | | [3](#Ripple) |
| Tron | secp256k1 | TODO | | TODO |
| Ontology | nist256p1 | TODO | | TODO |
| Cardano | ed25519 | `44'/1815'/a'/y/i` | yes | [4](#Cardano) |
| Stellar | ed25519 | `44'/148'/a'` | | |
| NEM | ed25519 | `44'/43'/a'` | | [5](#NEM) |
| Monero | ed25519 | `44'/128'/a'` | | |
| Tezos | ed25519 | `44'/1729'/a'` | | [6](#Tezos) |
`c` stands for the [SLIP-44 id] of the currency, when multiple currencies are handled
by the same code. `a` is an account number, `y` is change address indicator (must be
0 or 1), and `i` is address index.
[slip-44 id]: https://github.com/satoshilabs/slips/blob/master/slip-0044.md
Paths that do not conform to this table are allowed, but user needs to confirm a warning
on Trezor.
### Public nodes
Some currencies allow exporting a _public node_, which lets the client derive all
non-hardened paths below it. In that case, the conforming path is equal to the
hardened prefix.
I.e., for Bitcoin's path `44'/c'/a'/y/i`, the allowed public node path is `44'/c'/a'`.
Trezor does 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. <a name="Bitcoin"></a> For Bitcoin and its derivatives it is a little bit more
complicated. `p` is decided based on the following table:
| p | type | input script type |
| --- | --------------- | ----------------- |
| 44 | legacy | SPENDADDRESS |
| 48 | legacy multisig | SPENDMULTISIG |
| 49 | p2sh segwit | SPENDP2SHWITNESS |
| 84 | native segwit | SPENDWITNESS |
Other `p` are disallowed.
2. <a name="Ethereum"></a> We believe this should be `44'/c'/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. Also to support
"Ledger Live" legacy paths we allow `44'/60'/0'/a` paths.
3. <a name="Ripple"></a> Similar to Ethereum this should be `44'/c'/a'`. But for
compatibility with other HW vendors we use `44'/c'/a'/0/0`.
4. <a name="Cardano"></a> Cardano has [CIP-0003] algorithm that allows
non-hardened derivation on ed25519.
[cip-0003]: https://cips.cardano.org/cips/cip3/
5. <a name="NEM"></a> NEM's path should be `44'/43'/a'` as per SEP-0005, but we allow
`44'/43'/a'/0'/0'` as well for compatibility reasons with NanoWallet.
6. <a name="Tezos"></a> Tezos supports multiple curves, but Trezor currently supports
ed25519 only.
Sign message paths are validated in the same way as the sign tx paths are.
## Allowed values
For UTXO-based currencies, account number `a` needs to be in the interval \[0, 20]
and address index `i` in the interval \[0, 1 000 000].
For account-based currencies (i.e., those that do not use address indexes), account
number `a` needs to be in the interval \[0, 1 000 000]