[WalletConnect/BNB]: Add support for WalletConnect signing requests

[satoshiotomakan]

Description

Add an interface to parse signing requests received through WalletConnect protocol. For now, BNB chain is only supported.

How to use

1. Parse the received signing request by using WalletConnectRequest.parse method.
2. Adjust fee, add a privateKey to the result Proto::SigningInput message.
3. Generate and sign a transaction by using AnySigner.sign method.
4. Generate a WalletConnect JSON response with the result signature.

Example

Request received by WalletConnect framework (BNB Beacon SendOrder)

{
    "signerAddress": "bnb1grpf0955h0ykzq3ar5nmum7y6gdfl6lxfn46h2",
    "signDoc": {
        "account_number": "12",
        "chain_id": "chain-bnb",
        "memo": "",
        "data": null,
        "msgs": [
            {
                "inputs": [
                    {
                        "address": "bnb1grpf0955h0ykzq3ar5nmum7y6gdfl6lxfn46h2",
                        "coins": [ {"amount": 1001000000, "denom": "BNB"} ]
                    }
                ],
                "outputs": [
                    {
                        "address": "bnb1hlly02l6ahjsgxw9wlcswnlwdhg4xhx38yxpd5",
                        "coins": [ {"amount": 1001000000, "denom": "BNB"} ]
                    }
                ]
            }
        ],
        "sequence": "35",
        "source": "1"
    }
}

How to parse and handle the signing request

import wallet.core.jni.AnySigner
import wallet.core.jni.CoinType
import wallet.core.jni.proto.WalletConnect

// Step 1: Parse a signing request received through WalletConnect.

val parsingInput = WalletConnect.ParseRequestInput.newBuilder().apply {
    method = WalletConnect.Method.CosmosSignAmino
    payload = "{\"signerAddress\":\"bnb1grpf0955h0ykzq3ar5nmum7y6gdfl6lxfn46h2\",\"signDoc\":{\"account_number\":\"19\",\"chain_id\":\"chain-bnb\",\"memo\":\"\",\"data\":null,\"msgs\":[{\"inputs\":[{\"address\":\"bnb1grpf0955h0ykzq3ar5nmum7y6gdfl6lxfn46h2\",\"coins\":[{\"amount\":1001000000,\"denom\":\"BNB\"}]}],\"outputs\":[{\"address\":\"bnb13zeh6hs97d5eu2s5qerguhv8ewwue6u4ywa6yf\",\"coins\":[{\"amount\":1001000000,\"denom\":\"BNB\"}]}]}],\"sequence\":\"23\",\"source\":\"1\"}}"
}.build()

val parsingOutputBytes = WalletConnectRequest.parse(BINANCE, parsingInput.toByteArray())
val parsingOutput = WalletConnect.ParseRequestOutput.parseFrom(parsingOutputBytes)

assertEquals(parsingOutput.error, Common.SigningError.OK)

// Step 2: Set missing fields.

val signingInput = parsingOutput.binance.toBuilder().apply {
    privateKey = ByteString.copyFrom("95949f757db1f57ca94a5dff23314accbe7abee89597bf6a3c7382c84d7eb832".toHexBytes())
}.build()

// Step 3: Sign the transaction.

val output = AnySigner.sign(signingInput, BINANCE, SigningOutput.parser())

assertEquals(output.error, Common.SigningError.OK)

Prepare a WalletConnect JSON response (note this is blockchain specific).

import org.json.JSONObject

@Serializable 
data class CosmosResponse(val signed: JSONObject, val signature: JSONObject)

// Step 4: Construct a WalletConnect JSON response.

// Use the result `signatureJson`.
val signature = JSONObject(output.signatureJson)
// Use the original `signDoc` as a `signed` value.
val response = CosmosResponse(request.params.signDoc, signature)

Response to be sent via WalletConnect framework

{
    "signed": {
        "account_number": "12",
        "chain_id": "chain-bnb",
        "memo": "",
        "data": null,
        "msgs": [
            {
                "inputs": [
                    {
                        "address": "bnb1grpf0955h0ykzq3ar5nmum7y6gdfl6lxfn46h2",
                        "coins": [ {"amount": 1001000000, "denom": "BNB"} ]
                    }
                ],
                "outputs": [
                    {
                        "address": "bnb1hlly02l6ahjsgxw9wlcswnlwdhg4xhx38yxpd5",
                        "coins": [ {"amount": 1001000000, "denom": "BNB"} ]
                    }
                ]
            }
        ],
        "sequence": "35",
        "source": "1"
    },
    "signature": {
        "pub_key": {
						"type": "tendermint/PubKeySecp256k1",
						"value": "Amo1kgCI2Yw4iMpoxT38k/RWRgJgbLuH8P5e5TPbOOUC"
				},
        "signature": "1b1181faec30b60a2ddaa2804c253cf264c69180ec31814929b5de62088c0c5a45e8a816d1208fc5366bb8b041781a6771248550d04094c3d7a504f9e8310679"
    }
}

How to test

Run Rust, C++, Kotlin, iOS tests

Types of changes

Checklist

• Create pull request as draft initially, unless its complete.
• Add tests to cover changes as needed.
• Update documentation as needed.
• If there is a related Issue, mention it in the description.

If you're adding a new blockchain

• I have read the guidelines for adding a new blockchain.

[lamafab]

Oh boy, what a list 😅