Ask HN: Is there hashing function that can keep track of unique ids?

I'll just talk about use case probably easiest way to see what I'm asking. > Imagine you're creating a computer virus. > You'd like to know how many computers have gotten it. > But virus can't simply ping you, it's a limitation. > Only way you can know how many computers have it is to get infected yourself. > you can use mac address as unique id > virus somehow carries info on amount of unique computers it has been on. > virus can also consolidate its lineage information with existing virus in case it reinfects a computer that already had the virus. imagine a mesh of individual agents communicating with each other information about the whole group. While I'm sure a program can be created that carries a set of mac addresses with it in its code... my question is there a encryption/hashing method that can do this ex: h(s8dn98320n80fbn1890rbf18001) => 55 unique ids. ex: virus spreads like this a -> b a -> c b -> d c - > d c -> e e -> f e -> U U is your computer, you should know that your virus is at least on computers a, b, c, d... and if you get infected again down the line you should also get to know of new players in lineages.