question

We try to write a sample to test PlayFab LinkGameCenterAccount API in Unity, we don’t use the paid plugin Prime31 and use an open-source Unity native plugin (https://github.com/desertkun/GameCenterAuth) instead. This API can work fine with signature validation. You can try to refer to the following code.

using UnityEngine;
using UnityEngine.SignInWithApple;
using PlayFab;
using PlayFab.ClientModels;
using UnityEngine.SocialPlatforms.GameCenter;
using AOT;
using System;
using Online;

...

   public void Start()
    {
        Open();
    }

...

 private void OnLoginWithAppleSuccess(LoginResult result)
    {
        Debug.Log("Login Success!");

        Process();
    }



    [MonoPInvokeCallback(typeof(GameCenterSignature.OnSucceeded))]
    private static void OnSucceeded(
           string PublicKeyUrl,
           ulong timestamp,
           string signature,
           string salt,
           string playerID,
           string alias,
           string bundleID)
    {
        Debug.Log("Succeeded authorization to gamecenter: \n" +
            "PublicKeyUrl=" + PublicKeyUrl + "\n" +
            "timestamp=" + timestamp + "\n" +
            "signature=" + signature + "\n" +
            "salt=" + salt + "\n" +
            "playerID=" + playerID + "\n" +
            "alias=" + alias + "\n" +
            "bundleID=" + bundleID);

        PlayFabClientAPI.LinkGameCenterAccount(new LinkGameCenterAccountRequest
        {
            GameCenterId = playerID,
            PublicKeyUrl = PublicKeyUrl,
            Salt = salt,
            Signature = signature,
            Timestamp = timestamp.ToString()

        }, OnLinkingSuccess, OnPlayFabError) ;

    }

    private static void OnLinkingSuccess(LinkGameCenterAccountResult obj)
    {
        Debug.Log("LinkGameCenter success!");
    }

    [MonoPInvokeCallback(typeof(GameCenterSignature.OnFailed))]
    private static void OnFailed(string reason)
    {
        Debug.Log("Failed to authenticate with gamecenter:" + reason);
    }

    private void OnLocalAuthenticateResult(bool success)
    {
        if (success)
        {
            Debug.Log("LocalAuthenticate success!");

            GameCenterSignature.Generate(OnSucceeded, OnFailed);
        }
        else
        {
            Debug.Log("LocalAuthentificate failed.");
        }
    }

    public void Process()
    {
        if (Social.localUser.authenticated)
        {
            GameCenterSignature.Generate(OnSucceeded, OnFailed);
        }
        else
        {
            Social.localUser.Authenticate(OnLocalAuthenticateResult);
        }
    }

...