Comment by JoshMandel

But to be clear, mdoc already accounts for this through its selective disclosure protocol, without the need for a zero knowledge proof technology. When you share an mdoc you are really just sharing a signed pile of hashes ("mobile security object") and then you can choose which salted pre-images to share along with the pile of hashes. So for example your name and your birth date are two separate data elements and sharing your MSO will share the hashes for both, but you might only choose to share the pre-image representing your birthday, or even a simple boolean claim that you are over 21 years old.

What you don't get with this scheme (and which zero knowledge proofs can provide) is protection against correlation: if you sign into the same site twice or sign into different sites, can the site owners recognize that it is the same user? With the design of the core mdoc selector disclosure protocol, the answer is yes.