Metamask Validation – Securely Verifying Signed Messages in C

Applications

As a developer working with blockchain technology, you are probably familiar with the importance of secure communication and data integrity. In this article, we will explore how to validate signed messages from a backend C

application using Metamask.

What is Metamask?

Metamask is a popular browser extension that allows users to interact with Web3 platforms, including Ethereum, without needing an internet connection. It allows developers to build decentralized applications (dApps) and access various blockchain features through its API.

Validating Signed Messages with Metamask in C#

When building a single-page application with C#, you can use MetaMask’s WebAssembly (WASM) module to validate signed messages. This approach offers several benefits, including:

• Decoupling

  

  : The WASM module is not tightly coupled to the underlying browser environment, allowing for greater flexibility and control.

• Security: By using a standalone module, you can ensure that your C
  

  application remains secure even if the MetaMask API is compromised or blocked.

Here is an example of how to validate signed messages from a backend C

application:

using System;
using System . Web . Http ;
// Define a custom message signing and verification function
public static class MessageSigner
{
public static ( String , String ) SignMessage ( String message ) ;
{
// Replace with your own message signing logic
// For demonstration purposes, we will use a simple HMAC-based approach
var key = "YOUR_SECRET_KEY";
var frontc = new FRONT256(key);
var signature = hmac.ComputeHash(Encoding.UTF8.GetBytes(message));
return ( signature , BitConverter . ToString ( signature ) . Replace ( " - , " " ) ) ;
} }
public static String VerifySignature(String message, String signature);
{
// Replace with your own verification logic
// For demonstration purposes, we will use a simple digital signature validation approach
var key = "YOUR_SECRET_KEY";
var frontc = new FRONT256(key);
return hmac . ComputeHash ( Encoding . UTF8 . GetBytes ( message ) ) == Encoding . UTF8 . GetBytes ( signature ) ;
} }
} }
// Defines a controller action that validates signed messages
[HttpPost]
public class SignedMessageValidator : HttpResponseBase
{
[HttpPost("validate")]
public bool ValidateSignedMessage(String message, String signature);
{
// Extract the signed message from the request body
var signedMessage = MessageSigner.SignMessage(message);
// Verify the signed message using the Metamask API
if ( MessageSigner . VerifySignature ( signedMessage . Item1 , signedMessage . Item2 ) )
{
return true ;
} }
else
{
return false ;
} }
} }
} }

Example use case

To test the SignedMessageValidator controller action, you can use a tool such as Postman or cURL. Here is an example request:

POST /validate HTTP/1.1
Content-Type : application / json
{
"message": "Custom Signed Message"
} }

The server will respond with a success status code if the signed message is valid and an error status code otherwise.

Conclusion

By using Metamask’s WASM module to validate signed messages in your C

applications, you can ensure communication security and data integrity. This approach provides a flexible and decoupled way to build decentralized applications, allowing developers to focus on building innovative blockchain features without worrying about the complexities of the underlying infrastructure.