If you use same password to login to multiple servers and if one server is compromised via SHA collision (which the author assumes to be much faster than passwo

If you use same password to login to multiple servers and if one server is compromised via SHA collision (which the author assumes to be much faster than password brute force), then basically all the servers are compromised (since they have same hash). The author proposes to have different hashes in each different servers but user only have to know one password. This is achieved by this shadowd. So, if one server is compromised, the others are still safe. (Consider this as a beginning to understand the rest of the README)