# Error Handling & Security

## Overview

The VeWorld Wallet Link SDK uses encrypted communication for every message exchange.\
This section covers how to handle errors properly and secure sensitive data (keys, sessions, and payloads).

***

## Common Error Structure

Every event can return either a success or an error response.

```ts
type VeWorldResponse = {
  data: string;
  nonce: string;
  publicKey: string;
};

type VeWorldError = {
  errorCode: VeWorldErrorCode;
  errorMessage: string;
};
```

Before decrypting, **always check** whether the response contains an `errorCode`.

```ts
if ('errorCode' in response) {
  console.error('VeWorld Error:', response.errorCode, response.errorMessage);
  return;
}

const payload = decryptPayload(/* ... */);
```

***

## Error Codes

When making requests to VeWorld—establishing a connection, sending a transaction, or signing a message—VeWorld may respond with an error.\
These codes are inspired by Ethereum’s EIP‑1474 and EIP‑1193.

| Error Code | Error Name               | Error Description                                                                                         |
| ---------: | ------------------------ | --------------------------------------------------------------------------------------------------------- |
|       4100 | Unauthorized             | The requested method and/or account has not been authorized by the user.                                  |
|       4001 | User rejected connection | The user rejected the request through VeWorld.                                                            |
|       4900 | Disconnected             | VeWorld could not connect to the network.                                                                 |
|     -32002 | Resource Not Available   | A new request was sent while an approval dialog is already open. Wait for the current approval to finish. |
|     -32003 | Transaction Rejected     | VeWorld does not recognize a valid transaction.                                                           |
|     -32600 | Invalid Payload          | The payload is invalid.                                                                                   |
|     -32601 | Method Not Found         | VeWorld does not recognize the requested method.                                                          |
|     -32602 | Invalid Parameters       | Missing or invalid parameters.                                                                            |
|     -32603 | Internal Error           | Something went wrong within VeWorld.                                                                      |

> 💡 Tip: Keep a human-readable mapping of these errors for UI display (e.g., “Please approve connection in VeWorld”).

***

## Key Storage Guidelines

* **Never store keys in plain text.**\
  Use secure storage modules such as **Expo SecureStore** or **react-native-keychain**.
* **Generate keys once per installation.**\
  A key pair should be created once and reused until manually reset.
* **Do not log keys or decrypted data.**\
  Avoid logging payloads that contain private or sensitive information.
* **Encrypt or obfuscate storage where possible.**\
  Even temporary storage (`AsyncStorage`) should be considered untrusted.

***

## Session Management

* Each connection establishes a **session token** for communication.
* Sessions **do not expire automatically** but can be invalidated manually.
* On logout or disconnect, always clear:

```ts
setSession(null);
setVeWorldPublicKey(null);
setAddress(null);
```

Treat session data like an authentication token — store securely.

***

## Troubleshooting Common Issues

| Issue                   | Possible Cause                                 | Fix                                             |
| ----------------------- | ---------------------------------------------- | ----------------------------------------------- |
| Deep links not working  | Scheme not registered or redirect URL mismatch | Verify `scheme` and `redirectUrl` configuration |
| VeWorld app not opening | Incorrect deep link or app missing             | Test link manually on device                    |
| Connection fails        | Invalid public key or network error            | Regenerate keys and retry                       |
| Decryption fails        | Key mismatch between app and VeWorld           | Ensure same key pair used for connect + decrypt |
| Transaction rejected    | User denied request                            | Handle gracefully and provide retry option      |

***

## Security Checklist ✅

* Keys stored in SecureStore or Keychain
* Error handling checks `errorCode` before decrypting
* Session cleared on logout/disconnect
* Logging sanitized of sensitive data
* Deep link scheme unique to the app

***

[← Back: Event Handlers](https://github.com/vechain/vechain-docs/blob/main/developer-resources/sdks-and-providers/react-native-wallet-link/05-event-handlers.md) · [Next → Network Configuration](https://github.com/vechain/vechain-docs/blob/main/developer-resources/sdks-and-providers/react-native-wallet-link/07-network-configuration.md)