World said on Sept. 7 it has open-sourced ProveKit, a zero-knowledge proof toolkit that can prove a user’s age, nationality or whether they hold a valid ID without revealing personal information.

World said it has opened to external developers the technology applied to World ID, its “Proof of Human” system, and expects developers to use ProveKit to build privacy-protecting identity verification features into various apps and services.

World said, for example, in services that need to confirm whether a user is an adult, users can prove only that they are “18 or older” instead of submitting their date of birth or a full ID. It said users can also prove they meet required conditions when nationality or valid ID possession must be checked, without disclosing original personal information such as nationality details or passport numbers to the other party.

ProveKit also processes the computations needed for proofs directly on a user’s smartphone or browser rather than outsourcing them to external servers. World said sensitive personal information is not sent to external servers for the verification process, and the service checking the information receives only the result that the user meets the required conditions.

Sang-wook Park (박상욱), head of Tools for Humanity Korea, said submitting more personal information than necessary to confirm age or nationality online increases security and privacy burdens as data accumulates. He said ProveKit keeps original information on a user’s device and proves only the facts needed by a service, helping developers apply personal data protection from the service design stage.