Forword. The following question I have asked at first at Law Stackexchange, because it has to do mainly with legal aspects of encryption and my assumption was, that there is the right place, https://law.stackexchange.com/questions/28181/bob-and-alice-are-trying-out-pgp-and-fail But the moderator in the law section had a different opinion so I want to ask the community here for help. I think the best would be, if a formulate the problem from scratch, so that anybody get an impression about what the problem is.
Encryption with PGP on the technical level is simple. Mainly because the software is available out of the box in any Linux distribution, is explained in detail by the manual and the RSA algorithm for distributing the public/private keys works reasonable well. I think, it is nearly impossible to not understand the usage of PGP or to encrypt a message the wrong way. But what is unclear, at least for me, is the legal aspect of using the software. My own investigation to the topic gave no exact result. I only found some hints, that strong encryption is discussed in anti-terrorism law and that means it is perhaps forbidden to use it in reality.
So my question is: Is PGP allowed for using it with a commercial purpose, or is the usage of software forbidden in general?