Enter zero-knowledge proofs, a technology so mind-bending it seems taken from the pages of a science fiction novel. Essentially, it is “a way to prove something to someone without revealing any of the information that goes into that proof,” says Emin Gün Sirer, a computer scientist at Cornell University. As a simple example, imagine that you must prove you are at least 18 years old. Instead of whipping out your ID, the math underlying zero-knowledge proofs can allow you to make someone 100 percent certain that you are older than 18 without revealing a shred of other information about yourself. Not your name, address, a photo—nothing.

https://www.technologyreview.com/s/609448/a-mind-bending-cryptographic-trick-promises-to-take-blockchains-mainstream/