Would it be possible to do the encryption outside of a normal phone, via some AD/DA converted plugged into the standard 3.5mm-headphone minijack? I started a t

Would it be possible to do the encryption outside of a normal phone, via some AD/DA converted plugged into the standard 3.5mm-headphone minijack? I started a thread to discuss this idea: https://news.ycombinator.com/item?id=7066792 https://news.ycombinator.com/item?id=7066792