Typically, Private Set Intersection (PSI) protocols let you learn the subset of items on each party's dataset that are in the intersection. The problem in this case is a relaxation of these kind of constructions. I would like to learn only the number of elements on the intersection.
I could achieve this by using proxy re-encryption on a 2-party setting, however it is non-trivial (at least to me) to do the same on an n-party setting without disclosing the intersection of any parties subset.
I wonder if this problem has a specific name and whether it has been studied before (some literature you can point me to). Any idea on how to achieve this is also welcome.