Jon Fingas / Android Authority
Most of us know and use Apple’s AirDrop feature to wirelessly share files, photos, and more between nearby Mac and iOS devices. But how does it work? It’s not like those files are literally dropped through the air, after all. Although, the name creates a concept close enough to the truth for people to grasp its function. In this article, we’ll dive into the details of the underlying technology of AirDrop and how it works.
Read more: How to use AirDrop to transfer files on iOS and macOS
AirDrop uses TLS encryption over a direct Bluetooth-enabled peer-to-peer Wi-Fi connection for transferring files. The Wi-Fi radios of the source and target devices communicate directly without using an internet connection.
What is AirDrop?
AirDrop is a feature native to iOS and macOS intended to simplify the process of sharing content. Before AirDrop, the only way to share photos with someone, for example, was by text or email. With AirDrop, Apple users can wirelessly share and receive photos, files, links, videos, notes, playlists, locations, and more with nearby Apple devices. There is no apparent limit on the size of the file AirDrop can transfer.
AirDrop is accessible on Apple devices running iOS 7 or newer. Since its launch, the technology has been utilized in scandalous and unsavory ways. Specifically, numerous cases have been reported in the media where iOS device users with AirDrop privacy set to “Everyone” have received unwanted files from nearby strangers; the phenomenon has been termed “cyber-flashing.”
For example, in June 2022, a man on a Southwest flight reportedly AirDropped a sexually explicit photo to all passengers aboard, leading to police waiting to escort him off the plane upon his arrival. Because of such events, Apple has quietly started limiting the “Everyone” mode to only being active for 10 minutes in different regions.
AirDrop has also been instrumental in protests. For example, users in China used AirDrop to distribute posters and slogans following the 2022 Beijing Sitong Bridge protest. Apple reportedly limited the AirDrop function in China just weeks before the subsequent COVID-19 demonstrations in China.
How does AirDrop work?
Dhruv Bhutani / Android Authority
So how do Apple devices use AirDrop to communicate? Well, the communication takes place over Apple Wireless Direct Link using generated link-local IPv6 addresses instead of the Wi-Fi chip’s fixed MAC address. In plain English, that means the device wanting to send an AirDrop emits a Bluetooth signal to detect devices within the vicinity. It also creates an iCloud identity based on the email addresses and phone numbers associated with the user’s Apple ID.
Once a device with AirDrop turned on is found, a peer-to-peer Wi-Fi connection is created between them. So while you have to have Wi-Fi turned on on both devices, they don’t need to rely on your router for internet. The underlying software AirDrop uses is Bonjour, Apple’s built-in service discovery tool for macOS and iOS operating systems.
Related: How to turn on AirDrop on a Mac
When using AirDrop, the sender selects who they want to share with. The sending device initiates an encrypted (TLS) connection with the receiving device, which exchanges iCloud identities. The identity is verified against each user’s Contacts app. Then the receiving user is asked to accept the incoming transfer from the identified person or device. This process is repeated for each device if multiple recipients have been selected.
In the Everyone mode, the same process is used, but if a match in Contacts isn’t found, the receiving devices are shown in the AirDrop send sheet with a silhouette with the device’s name. So although strangers don’t see your identity, they can still send you AirDrops should you decide to receive them.
Read more: Is Apple AirDrop not working? We’ve got nine fixes to try
A crypto AirDrop uses AirDrop to deliver tokens to the wallets of current cryptocurrency traders, either for free or in exchange for a small promotional service. It is usually a marketing method to spread awareness or increase ownership of the currency startup.
AirDrop works on Macs running macOS X Lion (10.7) or later. Here are a list fo Mac computers that are compatible with AirDrop:
- MacBook Pro: Late 2008 or newer, excluding late 2008 17-inch.
MacBook Air: Late 2010 or newer.
Aluminum MacBook: Late 2008.