question: How does “airdrop” on phones work? Can I airdrop pictures to anyone ? Can you airdrop music too ?
comment: AirDrop is essentially fancy Bluetooth file exchange that can switch to WiFi if both devices are on the same network. If a device is announcing via ZeroConf/Bonjour that it has the Airdrop service running, any other device can connect to it and transfer files. However, there is a slight twist: AirDrop authenticates against your Apple ID, and a device can be set to reject transfers from Apple IDs not in an accepted list. It allows you to transfer any file between two devices that support the protocol. Depending on the device, files may be handled differently on the receiving end, and iOS for example may limit what file types can be shared from within a given app interface. The Files app can send any file to AirDrop though.
passages: On iOS 7 and later, AirDrop can be accessed by either tapping on Settings  General  AirDrop, or swiping up the home screen through Control Center. Both Wi-Fi and Bluetooth are automatically switched on when AirDrop is enabled as they are both utilized.
  
  Options for controlling AirDrop discovery by other devices include:
  
  BULLET::::- No one can see device (Airdrop disabled)
  
  BULLET::::- Only contacts can see device
  
  BULLET::::- Everyone can see device.
   AirDrop
  
  AirDrop is an ad-hoc service in Apple Inc.'s iOS and macOS operating systems, introduced in Mac OS X Lion (Mac OS X 10.7) and iOS 7, which enables the transfer of files among supported Macintosh computers and iOS devices over Wi-Fi and Bluetooth, without using mail or a mass storage device.
   BULLET::::- SampleWiz – a touch screen enabled sampler and self sampler for the iPhone and iPad
  
  BULLET::::- MorphWiz – a dynamic touch screen music creation controller for iOS, Android, and Windows 8 enabled touch pads and laptops
  
  BULLET::::- Geo Synthesizer – a new digital music controller interface, for the iPhone and iPad.
  
  BULLET::::- Tachyon – app for mixing, morphing and transitioning between two types of sound, for the iPhone and iPad.
   In Apple Inc. iPhones released with iOS version 7.0 and higher, multipeer connectivity APIs (application programmable interfaces) are enabled and provided to allow Apple iPhones to operate in peer-to-peer ad hoc mesh networking mode. This means iPhones can now talk to each other without using a cellular signal or connection. Currently, Apple uses multipeer to allow one to send photos and large files (up to GB) to peers. This application is called AirDrop and has been gaining popularity. With 700+ millions of iPhones being used globally, ad hoc peer-to-peer networks will gain pervasive presence almost instantly. 
   AirDrop can be enabled unofficially on iPad (3rd generation). Although not supported by default, AirDrop can be enabled by jailbreaking the device and installing "AirDrop Enabler 7.0+" from cydia. This procedure is not supported by Apple.
  
  Section::::System limitations.:Transfer between two Mac computers.
  
  Running Mac OS X Lion (10.7) or later:
  
  BULLET::::- MacBook Pro: Late 2008 or newer, excluding late 2008 17-inch
  
  BULLET::::- MacBook Air: Late 2010 or newer
  
  BULLET::::- : Late 2008
  
  BULLET::::- MacBook and iMac: Early 2009 or newer
  
  BULLET::::- Mac Mini: Mid 2010 or newer
   BULLET::::- Mac Pro: Early 2009 with AirPort Extreme card, or mid 2010 or newer
  
  Section::::System limitations.:Transfer between a Mac and an iOS device.
  
  To transfer files between a Mac and an iPhone, iPad or iPod touch, the following minimum requirements have to be met: All iOS devices with AirDrop are supported with iOS 8 or later:
  
  Running OS X Yosemite (10.10) or later:
  
  BULLET::::- MacBook Air: Mid 2012 or newer
  
  BULLET::::- MacBook (Retina): all models
  
  BULLET::::- MacBook Pro: Mid 2012 or newer
  
  BULLET::::- iMac: Late 2012 or newer
  
  BULLET::::- iMac Pro: all models
  
  BULLET::::- Mac Mini: Late 2012 or newer
   BULLET::::- Mac Pro: Late 2013 or newer
  
  Bluetooth and Wi-Fi have to be turned on for both Mac and iOS devices. (Both devices are not required to be connected to the same Wi-Fi network.)
  
  Section::::Security and privacy.
  
  AirDrop uses TLS encryption over a direct Apple-created 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 or Wi-Fi Access Point.
   Wi-Fi must be turned on in order for AirDrop to recognize the other device. The other device must also have AirDrop selected in a Finder window sidebar to be able to transfer files. Furthermore, files are not automatically accepted; the receiving user must accept the transfer. This is done to improve security and privacy.
  
  Section::::System limitations.
  
  Section::::System limitations.:Transfer between two iOS devices.
  
  Running iOS 7 or later:
  
  BULLET::::- iPhone 5 or newer
  
  BULLET::::- iPad (4th generation) or newer
  
  BULLET::::- iPad Pro: all models
  
  BULLET::::- iPad Mini (1st generation) or newer
  
  BULLET::::- iPod Touch (5th generation) or newer
   The technical details of AirDrop and the proprietary peer-to-peer Wi-Fi protocol called "Apple Wireless Direct Link (AWDL)" have been reverse engineered and the resulting open source implementations published as "OWL"
  
  and "OpenDrop".
  
  There have been numerous reported cases where iOS device users with AirDrop privacy set to “Everyone” have received unwanted files from nearby strangers; the phenomenon has been termed "cyber-flashing." Users have the full ability to control their AirDrop settings and limit who can send them files, with options for "Everyone", "Contacts Only", or "Off".
  
  Section::::See also.
  
  BULLET::::- Android Beam, a similar technology for Android smart phones (NFC based)
   BULLET::::10. DROPOUTJEEP: "A software implant for the Apple iPhone that utilizes modular mission applications to provide specific SIGINT functionality. This functionality includes the ability to remotely push/pull files from the device. SMS retrieval, contact list retrieval, voicemail, geolocation, hot mic, camera capture, cell tower location, etc. Command, control and data exfiltration can occur over SMS messaging or a GPRS data connection. All communications with the implant will be covert and encrypted."
  
  BULLET::::11. is a "tri-band active GSM base station with internal 802.11/GPS/handset capability"
   In iOS 7 or later, if an application implements AirDrop support, it is available through the share button. AirDrop is subject to a number of restrictions on iOS, such as the inability to share music or videos from the native apps.
  
  Section::::Routine.:macOS.
  
  On Macs running macOS 10.7 and greater, AirDrop is available in the Finder window sidebar. On Macs running OS X 10.8.1 or later, it can also be accessed through the menu option Go → AirDrop or by pressing ++.
   An early version of the "messaging app" was developed in beginning of July 2014 and the first La-La message to be sent via the service was a stream of the 17 second chorus of ‘Hello’ by Lionel Richie.
  
  Section::::Reception.
  
  Since its summer release, "La-La" has been reported to have passed over 40,00 users and has been featured in respectable technology publications including "TechCrunch", "Product Hunt", "RTTNews" & "About.com".
   The third version of the device has GSM, 3G, and wi-fi capabilities, creating several ways of accessing and operating it remotely, depending on available technology: SMS text message, an Internet browser, or directly via wireless network.
  
  Section::::Implementations.
  
  Pocket FM was first deployed in Syria in September 2013. Since then MiCT has also started a project in Sierra Leone and smaller initiatives in Yemen and Tanzania. MiCT has produced about two dozen units.
  
  Section::::Implementations.:Syria.
   Prior to OS X Yosemite (OS X 10.10), and under OS X Lion, Mountain Lion, and Mavericks (OS X 10.7–10.9, respectively) the AirDrop protocol in macOS was different from the AirDrop protocol of iOS, and the two were therefore not interoperable with each other. OS X Yosemite and later support the iOS AirDrop protocol, which is used for transfers between a Mac and an iOS device as well as between two 2012 or newer Mac computers, and which uses both Wi-Fi and Bluetooth. 
  
  There is no restriction on the size of the file which AirDrop will accommodate.
  
  Section::::Routine.
  
  Section::::Routine.:iOS.
   A common data application on mobile phones is Short Message Service (SMS) text messaging. The first SMS message was sent from a computer to a mobile phone in 1992 in the UK while the first person-to-person SMS from phone to phone was sent in Finland in 1993. The first mobile news service, delivered via SMS, was launched in Finland in 2000, and subsequently many organizations provided "on-demand" and "instant" news services by SMS. Multimedia Messaging Service (MMS) was introduced in 2001.
  
  Section::::Software.:Application stores.
   Newer portable media players are now coming with Internet access via Wi-Fi. Examples of such devices are Android OS devices by various manufacturers, and iOS devices on Apple products like the iPhone, iPod Touch, and iPad. Internet access has even enabled people to use the Internet as an underlying communications layer for their choice of music for automated music randomisation services like Pandora, to on-demand video access (which also has music available) such as YouTube. This technology has enabled casual and hobbyist DJs to cue their tracks from a smaller package from an Internet connection, sometimes they will use two identical devices on a crossfade mixer. Many such devices also tend to be smartphones.
   BULLET::::1. Short message mobile-terminated (SMS-MT)/ Point-to-Point: the ability of a network to transmit a Short Message to a mobile phone. The message can be sent by phone or by a software application.
  
  BULLET::::2. Short message mobile-originated (SMS-MO)/ Point-to-Point: the ability of a network to transmit a Short Message sent by a mobile phone. The message can be sent to a phone or to a software application.
  
  BULLET::::3. Short message cell broadcast.
   BULLET::::- Notification on similar nodes transmitting in vicinity
  
  Possible combinations depend on the application on the phone.
  
  Section::::Usage principle.:Standardization.
   BULLET::::- A DARPA project explores the possibility of using balloons as non-line-of-sight communication relay among ground units and between ground units and aircraft.
  
  BULLET::::- As of 2013, military researchers are investigating lighter-than-air craft for carrying cargo and, possibly, troops in the Integrated Sensor is Structure (ISIS) and Long Endurance Multi-intelligence Vehicle (LEMV) programs.
  
  Section::::See also.
  
  BULLET::::- Balloon (aircraft)
  
  BULLET::::- Balloon campaigns in Korea
  
  BULLET::::- Fire balloon – History of balloon bombs launched by Japan against the United States in World War II
  
  BULLET::::- Operation Outward – British World War II programme to attack Germany by means of free-flying balloons
   BULLET::::- OK Go's first video for "This Too Shall Pass" is a single-shot music video collaboration with 125 members of the University of Notre Dame's marching band and 50 students from Perley Elementary and Good Shepherd Montessori School in South Bend, Indiana. The video that took 20 takes to complete correctly. The band contacted Notre Dame after seeing a YouTube clip of the marching band performing "Here It Goes Again" at a football game.
  
  Section::::Videos.:Videos from "Of the Blue Colour of the Sky".:"This Too Shall Pass" Rube Goldberg Machine.
  
  BULLET::::- "Released March 1, 2010 in partnership with State Farm Insurance."
   BULLET::::- Release of Bloody Bunny, Biscuit and Unsleep Sheep applications for iPhone and Blackberry
  
  BULLET::::- Awarded runner-up prize at SIPA Game Contest 2009 & SIPA Animation Contest 2009
  
  2010
  
  BULLET::::- Exhibit at Toy & Comic Expo Asia 2010 (Thailand)
  
  BULLET::::- Exhibit at Singapore Toy Games & Comic Convention (STGCC) 2010
  
  BULLET::::- Launch of P4 Panda Foremost milk at 7-Eleven Thailand
  
  Section::::Characters.
  
  2Spot has created over 200 characters. The four most popular ones are Biscuit, Bloody Bunny, P4, and Unsleep Sheep.
   On Android, users can opt into making Signal the default SMS/MMS application, allowing them to send and receive unencrypted SMS messages in addition to the standard end-to-end encrypted Signal messages. Users can then use the same application to communicate with contacts who do not have Signal. Sending a message unencrypted is also available as an override between Signal users.
   BULLET::::- Jitsi, a Java VoIP and Instant Messaging client with ZRTP encryption, for FreeBSD, Linux, OS X, Windows; LGPL
  
  BULLET::::- KPhone, using Qt libraries, GPL, for Linux
  
  BULLET::::- Linphone, with a core/UI separation, the GUI is using GTK+ libraries, for Linux, OS X, Windows, and mobile phones (Android, iPhone, Windows Phone, BlackBerry)
  
  BULLET::::- MicroSIP, lightweight softphone, using PJSIP stack, for Windows
  
  BULLET::::- QuteCom, formerly named OpenWengo, using Qt libraries, GPL, for Windows, Mac, and RPM- DEB-based Linux
  
  BULLET::::- Telephone, OS X softphone written in Cocoa/Swift
  
  BULLET::::- Twinkle, using Qt libraries, GPL, for Linux
  
  BULLET::::- Yate client, using Qt libraries, GPL
   With the prior .Mac service, the iPhoto, iMovie, GarageBand and iTunes libraries could easily be uploaded to any iDisk (subject to various licensing agreements).
  
  Section::::Integration.:iOS.
   All iMessages are encrypted and can be tracked using delivery receipts. If the recipient enables Read Receipts, the sender will be able to see when the recipient has read the message. iMessage also allows users to set up chats with more than two people—a "group chat".
  
  With the launch of iOS 10, users can send messages accompanied by a range of "bubble" or "screen" effects. By holding down the send button with force, the range of effects is surfaced for users to select an effect to be sent to the receiver. 
  
  Section::::Technology.
  