A novel package that integrates components for a modulating retro reflector into a single package is disclosed according to various embodiments. This method enables easy and substantially error-free end-user authentication, which forms the basis for enabling electronic transactions that are less vulnerable to fraud. The process and equipment also provides the ability to readily switch between using ATS and ABS as the primary absorbent solution for SO2 absorption, depending upon the concentration of SO2 in the off gas feed streams.