AirDrop is leaking email addresses and phone numbers Ars Technica This story first appeared Ars Technica, a reliable source for technology news, technology policy analysis, reviews, and more. Ars is the parent company of WIRED, Condé Nast. AirDrop uses Wi-Fi and Bluetooth Low Energy to establish direct connections with nearby devices so you can send photos, documents, and more iOS or macOS the device to another. One mode allows you to connect only to contacts, the second allows you to connect to anyone, and the last does not allow any connection. To determine whether the device of an AirDrop transmitter should connect to other nearby devices Bluetooth advertisements with a partial cryptographic hash of the sender’s phone number and email address. If there is a starter that has been hacked with any phone number or email address in the recipient’s address book, or if the device is set to receive from everyone, the two devices will perform a Wi-Fi mutual authentication intervention. When you shake hands, the devices exchange the full hash of SHA-256 phone numbers and email addresses of the owners.