I've been invited to speak in Iran several times but, not wanting to accept if it meant I would end up in Guantanamo on the way home, I requested my university seek official authorization. It turns out the U.S. has both DOD (ITAR) and Treasury Dept. sanctions against Iran and not only are the regulations extensive, they're not consistent.
The simple question I asked was, if I left all electronics home (because many/most/all are banned), could I carry a Powerpoint presentation with me on a flash drive or burned to a CD.[*] After all, it would be pointless to go there to give a talk if I couldn't give a talk. Once my university realized I was serious about wanting to go, the Provost decided the easiest way to deal with the situation was to ban all travel to Iran. Then, adding insult to injury, he gave my name to the head of the Middle East Studies department as the reason for the ban, resulting in an angry call from her to berate me for screwing it up for everyone.
But, I digress...
[*]The Powerpoint program itself is banned, but every Iranian gives their conference talks using Powerpoint, a program (along with Word, Excel, and everything else you can think of) universally available in the country.