Use the provided code to set up an HttpAgent with a DelegationIdentity or anonymous identity

Oct 13, 2025 by wbrum.org 17 views

Introduction

When integrating the EdjCase.ICP.Agent package into a Unity project, developers may encounter a certificate signature mismatch error when using the HttpAgent. This issue arises when attempting to call a canister method, such as create_user, using the CallAsync method on the agent. In this article, we will delve into the steps to reproduce this error, the expected behavior, and the actual behavior observed.

Steps to Reproduce

To reproduce this issue, follow these steps:

Integrate the EdjCase.ICP.Agent package into a Unity project: Include the EdjCase.ICP.Agent package in your Unity project by adding the necessary NuGet packages.
Use the provided code to set up an HttpAgent with a DelegationIdentity or anonymous identity: Utilize the provided code to create an instance of the HttpAgent, either with a DelegationIdentity or an anonymous identity.
Call the CallAsync method on the agent to invoke a canister method (e.g., create_user): Use the CallAsync method on the agent to invoke the create_user method on the canister.
Observe the Logcat output, where the error Certificate signature does not match the IC public key is logged: Monitor the Logcat output to observe the certificate signature mismatch error.

Expected Behavior

The expected behavior is that the HttpAgent should successfully authenticate and execute the canister call without certificate signature mismatches, allowing the create_user method to complete successfully.

Actual Behavior

The actual behavior observed is that the application throws a Certificate signature does not match the IC public key exception, causing the CallAsync operation to fail. The retry logic in the code attempts to handle this by delaying and retrying, but the issue persists.

Code Analysis

The provided code snippet demonstrates the use of the EdjCase.ICP.Agent package in a Unity project. The AutoCreateUserAsync method is responsible for creating a user on the canister using the create_user method. The code utilizes the CallAsync method on the agent to invoke the canister method.

using UnityEngine;
using UnityEngine.UI;
using EdjCase.ICP.Agent.Agents;
using EdjCase.ICP.Agent.Agents.Http;
using EdjCase.ICP.Agent.Identities;
using EdjCase.ICP.Candid.Models;
using System;
using UnityEngine.SceneManagement;
using System.Threading.Tasks;
using System.Collections;
using System.Net.Http;

namespace IC.GameKit
{
    public class TestICPAgent : MonoBehaviour
    {
        // [Previous code omitted for brevity]

        private async Task AutoCreateUserAsync(bool useAnonymous = false)
        {
            Debug.Log("1️⃣ Initializing AutoCreateUserAsync...");

            using var underlyingHttpClient = new HttpClient { BaseAddress = new Uri(icHost) };
            var httpClient = new DefaultHttpClient(underlyingHttpClient);
            var agent = useAnonymous ? new HttpAgent(httpClient) : new HttpAgent(httpClient, DelegationIdentity);
            Debug.Log($"✅ HttpAgent created with host: {icHost}");

            var canisterId = Principal.FromText(greetBackendCanister);
            var client = new GreetingClient.GreetingClient(agent, canisterId);
            Debug.Log("✅ GreetingClient created with DefaultHttpClient.");

            // [Other initialization code omitted]

            try
            {
                Debug.Log("7️⃣ Preparing create_user call...");
                CandidArg arg = CandidArg.FromCandid(
                    CandidTypedValue.FromObject(userPrincipal),
                    CandidTypedValue.FromObject(uuid)
                );
                Debug.Log("🔄 Calling create_user on canister...");
                const int maxRetries = 3;
                for (int attempt = 1; attempt <= maxRetries; attempt++)
                {
                    try
                    {
                        CandidArg reply = await agent.CallAsync(canisterId, "create_user", arg);
                        Debug.Log($"✅ create_user response: {reply}");
                        break;
                    }
                    catch (Exception ex)
                    {
                        Debug.LogError($"❌ Attempt {attempt}/{maxRetries} Failed to call create_user: {ex.Message}\nStackTrace: {ex.StackTrace}");
                        if (attempt == maxRetries)
                        {
                            Debug.LogWarning("⚠ Max retries reached. Skipping create_user...");
                            break;
                        }
                        else if (ex.Message.Contains("Certificate signature does not match"))
                        {
                            Debug.LogWarning("⚠ Certificate mismatch detected. Retrying after delay...");
                            await Task.Delay(1000);
                        }
                        else
                        {
                            throw;
                        }
                    }
                }

                // [Remaining code omitted]
            }
            catch (Exception e)
            {
                Debug.LogError($"❌ Unexpected error in AutoCreateUserAsync: {e.Message}\nStackTrace: {e.StackTrace}");
            }
        }

        // [Other methods omitted]
    }
}

Conclusion

The certificate signature mismatch error when using the EdjCase.ICP.Agent with the HttpAgent is a complex issue that requires a thorough understanding of the underlying technology. By following the steps to reproduce this error, developers can identify the root cause of the issue and implement a solution to resolve the certificate signature mismatch error.

Recommendations

To resolve the certificate signature mismatch error, consider the following recommendations:

Verify the IC public key: Ensure that the IC public key is correctly configured and matches the expected value.
Check the certificate chain: Verify that the certificate chain is correctly configured and that the certificate is valid.
Update the EdjCase.ICP.Agent package: Ensure that the EdjCase.ICP.Agent package is up-to-date and that any known issues have been resolved.
Implement retry logic: Implement retry logic to handle certificate signature mismatch errors and other transient issues.

Introduction

In our previous article, we explored the certificate signature mismatch error when using the EdjCase.ICP.Agent with the HttpAgent. This error can be frustrating and challenging to resolve, especially for developers who are new to the EdjCase.ICP.Agent package. In this article, we will provide a Q&A section to help answer common questions and provide additional insights into resolving this issue.

Q: What is the certificate signature mismatch error?

A: The certificate signature mismatch error occurs when the IC public key does not match the expected value. This can happen due to various reasons, such as a mismatch in the certificate chain or an incorrect configuration of the IC public key.

Q: How can I reproduce the certificate signature mismatch error?

A: To reproduce the certificate signature mismatch error, follow these steps:

Integrate the EdjCase.ICP.Agent package into a Unity project: Include the EdjCase.ICP.Agent package in your Unity project by adding the necessary NuGet packages.
Use the provided code to set up an HttpAgent with a DelegationIdentity or anonymous identity: Utilize the provided code to create an instance of the HttpAgent, either with a DelegationIdentity or an anonymous identity.
Call the CallAsync method on the agent to invoke a canister method (e.g., create_user): Use the CallAsync method on the agent to invoke the create_user method on the canister.
Observe the Logcat output, where the error Certificate signature does not match the IC public key is logged: Monitor the Logcat output to observe the certificate signature mismatch error.

Q: What are the expected and actual behaviors when using the EdjCase.ICP.Agent with the HttpAgent?

A: The expected behavior is that the HttpAgent should successfully authenticate and execute the canister call without certificate signature mismatches, allowing the create_user method to complete successfully.

Q: How can I resolve the certificate signature mismatch error?

A: To resolve the certificate signature mismatch error, consider the following recommendations:

Verify the IC public key: Ensure that the IC public key is correctly configured and matches the expected value.
Check the certificate chain: Verify that the certificate chain is correctly configured and that the certificate is valid.
Update the EdjCase.ICP.Agent package: Ensure that the EdjCase.ICP.Agent package is up-to-date and that any known issues have been resolved.
Implement retry logic: Implement retry logic to handle certificate signature mismatch errors and other transient issues.

Q: What are some common causes of the certificate signature mismatch error?

A: Some common causes of the certificate signature mismatch error include:

Mismatch in the certificate chain: A mismatch in the certificate chain can cause the IC public key to not match the expected value.
Incorrect configuration of the IC public key: An incorrect configuration of the IC public key can cause the certificate signature mismatch error.
Outdated EdjCase.ICP.Agent package: An outdated EdjCase.ICP.Agent package can cause known issues, including the certificate signature mismatch error.

Q: How can I prevent the certificate signature mismatch error?

A: To prevent the certificate signature mismatch error, consider the following best practices:

Verify the IC public key: Ensure that the IC public key is correctly configured and matches the expected value.
Check the certificate chain: Verify that the certificate chain is correctly configured and that the certificate is valid.
Update the EdjCase.ICP.Agent package: Ensure that the EdjCase.ICP.Agent package is up-to-date and that any known issues have been resolved.
Implement retry logic: Implement retry logic to handle certificate signature mismatch errors and other transient issues.

By following these best practices and recommendations, developers can prevent the certificate signature mismatch error and ensure that their application functions as expected.