Signing Transactions

Transaction signing in the Nero MPC SDK is protocol-dependent. DKLS signs raw transaction hashes for EOA transactions, while Pedersen creates ERC-4337 UserOperations for smart account execution.

Protocol-Specific Transaction Paths

Protocol	Behavior
`dkls`	Signs raw transaction hashes using `ethers.Transaction` to compute the unsigned hash
`pedersen`	Builds an ERC-4337 UserOperation, signs it via MPC, and submits to a bundler

Pedersen Transaction Pipeline

Component	Responsibility
`SmartWallet.buildUserOperation()`	Constructs UserOp with callData, gas estimates, nonce
`SigningClient`	Coordinates threshold signature of the UserOp hash
`SmartWallet.sendUserOperation()`	Submits signed UserOp to bundler

Direct Transaction Signing

const tx = {
  to: "0xRecipientAddress",
  value: "0x16345785D8A0000", // 0.1 ETH in hex
  gasLimit: "0x5208", // 21000
};

const signedTx = await sdk.signTransaction(tx);

Using the EIP-1193 Provider

The eth_sendTransaction method triggers protocol-specific workflows automatically. Pedersen builds ERC-4337 UserOperations, while DKLS generates signatures for raw transactions.

const provider = sdk.getProvider();

const txHash = await provider.request({
  method: "eth_sendTransaction",
  params: [{
    to: "0xRecipientAddress",
    value: "0x16345785D8A0000",
  }],
});

Provider RPC Handlers

Method	Behavior
`eth_accounts` / `eth_requestAccounts`	Returns active wallet address (DKLS returns `_dklsWalletAddress`, Pedersen returns EOA from SmartWallet)
`personal_sign`	Converts hex or UTF-8 messages to bytes before calling `signMessageInternal`
`eth_signTypedData_v4`	Parses JSON typed data and forwards to `signTypedDataInternal`
`eth_sendTransaction`	Routes to protocol-specific transaction workflow

With ethers.js

import { BrowserProvider } from "ethers";

const provider = new BrowserProvider(sdk.getProvider());
const signer = await provider.getSigner();

const tx = await signer.sendTransaction({
  to: "0xRecipientAddress",
  value: ethers.parseEther("0.1"),
});

await tx.wait();
console.log("Transaction confirmed:", tx.hash);

Provider Events

The EIP-1193 provider emits standard events:

Event	Trigger	Data
`connect`	Provider becomes active	`ProviderConnectInfo` (hex chainId)
`disconnect`	Provider deactivated	`ProviderRpcError`
`chainChanged`	Chain switch	`string` (hex chainId)
`accountsChanged`	Wallet generated/cleared	`string[]`

Connection Lifecycle

The SDK manages provider connectivity through a state machine with four states:

State	Description
`disconnected`	Initial state with no active provider
`connecting`	SDK initializing the provider
`connected`	`NeroProvider` ready for requests
`errored`	Initialization failure occurred

const provider = sdk.getProvider();
await sdk.connect();

console.log(sdk.status); // "connected"
console.log(sdk.connected); // true

Provider Error Codes

Code	Name	Description
4001	`USER_REJECTED`	User rejected request
4100	`UNAUTHORIZED`	Provider lacks authorization
4200	`UNSUPPORTED_METHOD`	RPC method not implemented
4900	`DISCONNECTED`	Provider disconnected from chain
4902	`CHAIN_NOT_ADDED`	Requested chain not added

Signing Error Codes

Error Code	Scenario	Thrown By
`NO_WALLET`	Signing attempted before wallet creation	SDK signing method guards
`INVALID_NONCE_COMMITMENT`	Backend provided malformed nonce	`SigningClient` validation
`INVALID_PARTIAL_SIGNATURE`	Backend partial signature verification failed	`SigningClient` verification logic

Signing Transactions

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