Important clue concerning the solar observatory.. The post office. Snail mail is a great way to avoid the NSA. It is impractical to monitor every content of every letter. So as a mean of covert communication if you don't it is very viable.
Important clue concerning the solar observatory.. The post office. Snail mail is a great way to avoid the NSA. It is impractical to monitor every content of every letter. So as a mean of covert communication if you don't it is very viable.