public static void Save<T>(T data, string path)
{
    string jsonData = JsonUtility.ToJson(data);

    string hash = SaveUtils.ComputeHash(jsonData);

    SaveWrapper<T> wrapper = new SaveWrapper<T>
    {
        data = data,
        hash = hash
    };

    string finalJson = JsonUtility.ToJson(wrapper, true);

    string dir = Path.GetDirectoryName(path);
    if (!Directory.Exists(dir))
        Directory.CreateDirectory(dir);

    File.WriteAllText(path, finalJson);
}

public static T Load<T>(string path)
{
    if (!File.Exists(path))
        return default;

    string json = File.ReadAllText(path);

    SaveWrapper<T> wrapper = JsonUtility.FromJson<SaveWrapper<T>>(json);

    if (wrapper == null || wrapper.data == null)
        return default;

    string jsonData = JsonUtility.ToJson(wrapper.data);
    string computedHash = SaveUtils.ComputeHash(jsonData);

    if (computedHash != wrapper.hash)
    {
        Debug.LogError("T'as modif' coquinou !!!");
        return default;
    }
    return wrapper.data;
}


[System.Serializable]
public class SaveWrapper<T>
{
    public T data;
    public string hash;
}

// Tu t'fais ton Utils
public static class SaveUtils
{
    public static string ComputeHash(string truc)
    {
		//Si t'es énervé
		const string SECRET_KEY = "PHOQUE_ME";

        using (var sha = SHA256.Create())
        {
            byte[] bytes = sha.ComputeHash(Encoding.UTF8.GetBytes(truc + SECRET_KEY));
            return System.Convert.ToBase64String(bytes);
        }
    }
}