[Johnny555]

The difference is that math is an abstract concept with no physical manifestation. I can encrypt something in my head, but I can't make a physical bomb in my head.

Even when an encryption algorithm is implemented on a computer, it's still not a physical object, it's just a mathematical algorithm.

A computer simulation of explosive chemical reaction is not going to get you arrested, why should an encryption algorithm?

[techdragon]

A computer simulation of a nuclear explosion could be considered illegal to possess under the "Born Secret" doctrine applied by the US government, depending on the circumstances.