In many countries strong cryptography [is outlawed](https://security.stackexchange.com/questions/3160/can-we-still-provide-confidentiality-when-cryptography-is-outlawed). That means you must store the data of your users in such a way, that government of that country can always decrypt it. And if you don't, you are a criminal.

Suppose, someone is an author of some security software (instant messenger, disk encryption, whatever), that utilizes strong security without any loopholes for governments and where encryption keys really belong to client only so author can provide no way of decrypting anything without changing the whole system's architecture. This software is sold or otherwise distributed on the net and it's legal to do that in the country of author's residence. Suppose also, that this software became so popular, that even Ben Laden decided to use it.

As I understand, the author can be arrested as soon as he crosses the boundary of any country where strong cryptography is illegal, being accused in helping terrorists, if for example, a legal case against Ben Laden is in process there and your cryptographic product is protecting the terrorist's data. Is that correct?

So, technically, if you invent a knife and some knife is used both to cut bread and to kill people, you are ok. But if you invent cryptography, that can serve the privacy of both good and bad people, you are in trouble?