I am thinking that if I buy 100 euros at the posted daily exchange rate, today its at 1.13$ then it would not be illegal. If the government says that 1 euro costs $1.13 then why can't I buy it from a private person. The only thing that I am not doing is paying a middle man for the service.

As long as I am not charging above the posted daily exchange rate it is not black market. Am I wrong?