Remote Audio Output Protocol
Encyclopedia
Remote Audio Output Protocol (RAOP), is an RTSP/RTP
Real-time Transport Protocol
The Real-time Transport Protocol defines a standardized packet format for delivering audio and video over IP networks. RTP is used extensively in communication and entertainment systems that involve streaming media, such as telephony, video teleconference applications, television services and...

 based protocol made by Apple Inc.  It powers the AirPlay
AirPlay
AirPlay is a proprietary protocol stack/suite developed by Apple Inc. that allows wireless streaming of audio, video, and photos, together with related metadata between devices...

 technology built into AirPort Express
AirPort
AirPort and AirPort Extreme are local area wireless networking products from Apple Inc. based on the IEEE 802.11 standard ....

 wireless (802.11b/g/n) access point as well as the Apple TV. The major difference from the RTSP protocol is an initial Asymmetric key verification made by iTunes
ITunes
iTunes is a media player computer program, used for playing, downloading, and organizing digital music and video files on desktop computers. It can also manage contents on iPod, iPhone, iPod Touch and iPad....

 to verify it is communicating with an AirPort Express
AirPort Express
The AirPort Express is a simplified and compact AirPort Extreme base station. It allows up to 10 networked users, and includes a feature called AirTunes...

 (as opposed to a simulation), and vice versa. The data channel is also encrypted by AES
Advanced Encryption Standard
Advanced Encryption Standard is a specification for the encryption of electronic data. It has been adopted by the U.S. government and is now used worldwide. It supersedes DES...

, with a random key protected by the asymmetric key mentioned above.

The RSA public key stored in iTunes has been extracted by Jon Lech Johansen
Jon Lech Johansen
Jon Lech Johansen , also known as DVD Jon, is a Norwegian programmer famous for his work on reverse engineering data formats....

, enabling 3rd party software to stream music to an Airport Express .

The RSA private key stored in the AirPort Express
AirPort Express
The AirPort Express is a simplified and compact AirPort Extreme base station. It allows up to 10 networked users, and includes a feature called AirTunes...

has been extracted by James Laird, enabling simulation of an Airport Express. .
The Shairport application is available

External links

  • RAOP-play, an open source implementation of the protocol aimed for GNU/Linux computers
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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