Alchemist adopts a GNU GPLv3 license with a permissive modification. Alchemist or parts of it can be used in commercial products and closed-source software components, as far as they are not mutated. Namely, the GPLv3 is extended with a linking/classpath exception, so it can be used freely as a library, but modified versions the software must instead be released with a GPLv3 compatible lincesing scheme. There is no requirement for the portion of the program calling Alchemist to be reverse-engineerable (the Alchemist license is more permissive than GNU LGPL). If you use the simulator for academic purposes, then you must refer the appropriate paper.