Simple and secure custom API Keys using ASP.NET Core

public class ApiKeyFilter : IAuthorizationFilter
{
    private const string ApiKeyName = "api_key";
    private const string ApiKeyValue = "abcdefghijklmnopqrstuvwxyz";
    public void OnAuthorization(AuthorizationFilterContext context)
    {
        if (!context.HttpContext.Request.Headers.TryGetValue(ApiKeyName, out var potentialApiKey))
        {
            context.Result = new UnauthorizedResult();
            return;
        }
        if (!ApiKeyValue.Equals(potentialApiKey))
        {
            context.Result = new UnauthorizedResult();
            return;
        }
    }
}