I like the idea of a Zero Knowledge range proof. But I read that, to prove my age in a range, a commitment is required by a trusted party (TP) stating my age. How does that work? is the commitment a certificate from the TP?
Also, if I need a user “A” to prove to the verifier his current location (longitude, latitude) in a range without stating the exact location, can the zero knowledge range proof be helpful in that problem? Who should commit to that secret (in This case, user “A”'s current location) so it should be accurate? Can the TP be a trusted timestamped service or Google?