The IUPAC/NIST team made a beta release of the next InChI software release: InChIKey A had heard about the InChIKey extension earlier, and it solves the issue some people have with the InChI: it is too long. Well, molecules can have many atoms indeed. It is important to realize the InChIKey is not a replacement: it simply is not unique. The collision probability is calculated to be rather small, though.