Historically, clearly so. But since 2010 there has been a "General License" for exporting "Personal Communication Services" technology (essentially based on the idea that individuals' communication weakens the government's hold on society, or, as OFAC put it, "are a vital tool for change").
I do know there are requirements that need to be met for exportation of cryptography [0]. Interesting fact related to this: Strong crypto used to be considered a weapon. This is why the DVD standard is 40 bits (iirc, it's possibly 64 bits).
http://www.treasury.gov/resource-center/sanctions/Programs/D...
I don't know how the General License applies to cryptographic technology in particular. Paging Collin Anderson...