Adding Ledger Signer support

[amanusk]

Is your feature request related to a problem? Please describe.
Ledger now has a Starknet App, supporting singing transactions with Stark Curve on Ledger. Any existing Starknet account can now be used with Ledger as a signer.

Describe the solution you'd like
Add a custom LedgerSigner to starknet.js

This can be part of a broader generic signer implementation, but provided as part of the SDK for simpler integration

Additional context
Reference implementation on starknet-rs:

https://github.com/xJonathanLEI/starknet-rs/blob/db1fa598232f0698d942cc974f481b5d888ac080/starknet-signers/src/ledger.rs

[ivpavici]

relevant:
#748

[PhilippeR26]

@amanusk Is it a JS/TS equivalence to the rust library coins-ledger?
Any documentation from ledger to have an understanding of how it works?

[PhilippeR26]

My (very) old Nano S is not compatible with the Starknet ledger APP.
So, I ordered a new Nano X, to test it.

Nice!

[PhilippeR26]

I can communicate with it :

TransportNodeHid {
  exchangeTimeout: 30000,
  unresponsiveTimeout: 15000,
  deviceModel: {
    id: 'nanoX',
    productName: 'Ledger Nano X',
    productIdMM: 64,
    legacyUsbProductId: 4,
    usbOnly: false,
    memorySize: 2097152,
    masks: [ 855638016 ],
    getBlockSize: [Function: getBlockSize],
    bluetoothSpec: [ [Object] ]
  },

I have now to dig, to

• recover the pubkey
• sign a hash (as the ledger APP is not able to build a transaction)

[PhilippeR26]

The job to perform is mainly to create code for these 2 red parts :

for 3 methods :

• getVersion
• getPubKey
• sign

[PhilippeR26]

It was difficult, but it works.
The documentation is full of errors or missing data : https://github.com/LedgerHQ/app-starknet/blob/develop/docs/apdu.md
The current code works only in Node for a Ledger connected with USB. I have to see how to handle Web USB & Web Bluethooth...

[PhilippeR26]

Made with a Starknet.js Signer :

[PhilippeR26]

Ledger Nano X is not accepted with a Bluetooth connection, in my Linux Mint (Chrome, Brave, FireFox).
I have no knowledge about React native; so I didn't tested in mobile.
So, it works in my config in Node script & in Web DAPP (both connected with USB).

[PhilippeR26]

@ivpavici
I will propose a PR for the corresponding Signer.