Remote Audio Output Protocol

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Remote Audio Output Protocol
Communication protocol
AbbreviationRAOP
Purpose Internet streaming
Developer(s) Apple Inc.
Based on RTSP / RTP
OSI layer Application layer (7)
Hardware AirPort Express, Apple TV

Remote Audio Output Protocol (RAOP) is an Internet streaming protocol based on RTSP / RTP authored by Apple Inc. [1] [2] It powers the AirPlay technology built into AirPort Express wireless (802.11b/g/n) access point as well as the Apple TV. [2]

The major difference from RTSP is an initial asymmetric key verification made by iTunes to verify it is communicating with an AirPort Express or an Apple TV (as opposed to a simulation), and vice versa. The data channel is also encrypted by AES, with a random key protected by the asymmetric key mentioned above.[ citation needed ]

The RSA public key stored in iTunes was extracted by Jon Lech Johansen, enabling third-party software to stream music to an AirPort Express. [3]

The RSA private key stored in the AirPort Express was extracted by James Laird, enabling simulation of an Airport Express. [4]

The Shairport-sync application which emulates Airport Express hardware is available. [5]

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References

  1. "Unofficial AirPlay Protocol Specification". nto.github.io. Retrieved 20 October 2019.
  2. 1 2 "Technical note to describe the Remote Audio Access Protocol (RAOP) as used in Apple iTunes to stream music to the Airport Express". XMMS2 organization wiki. xmms2. 7 October 2019. Retrieved 20 October 2019.
  3. "[vlc-devel] commit: Comment for myself ( Rémi Denis-Courmont )". Mailman.videolan.org. 2008-01-02. Retrieved 2012-02-10.
  4. "[vlc-devel] RAOP/Airtunes". Mailman.videolan.org. 8 April 2011. Retrieved 2012-02-10.
  5. "shairport-sync". github.com. Retrieved 2016-09-16.