Also, using a hash (such as bcrypt) that can be made arbitrarily expensive. With a cost of 14, it takes this computer four seconds of CPU time per attempt to ha

Also, using a hash (such as bcrypt) that can be made arbitrarily expensive. With a cost of 14, it takes this computer four seconds of CPU time per attempt to hash each password. While merely annoying for one user, that would really slow down rainbow table creation.