Skype (pronounced to rhyme with ripe) is a peer-to-peer internet telephony network, founded by Niklas Zennström and Janus Friis, the creators of Kazaa. The developers claim that, unlike Kazaa, Skype eschews adware and spyware. Skype code remains proprietary software, but potential users can download it for free from the official site. Skype users can speak to other Skype users for free. The software also includes a SkypeOut feature which allows Skype users to dial regular telephones, for a fee. This is 0.017 Euros (US$0.02) per minute to many countries, including to mobile or cell phones in some countries, rising to 0.55 Euros in certain countries, but there is almost no telephone that cannot be rung from Skype.

Versions exist for Microsoft Windows (Windows 2000, Windows XP and Windows CE (Pocket PC)), Mac OS X and GNU/Linux.

Unlike some other VoIP programs, Skype intelligently routes calls between users; it has a design goal of "just working". It will even try to find a way through most firewalls, unlike alternatives such as SIP (see article (http://www.toyz.org/mrblog/archives/00000097.html)).

As Skype communication may get routed via other users in the peer-to-peer network, it uses 256-bit AES encryption in order to actively encrypt the data in each Skype call or instant message. Skype uses 1536 to 2048 bit RSA to negotiate symmetric AES keys. The Skype server certifies users' public keys when they log in.

The first beta version of the Skype software appeared on August 29 2003 and version 1.0 for Windows had its release on July 27 2004. October 20 2004 saw for the first time 1 million Skype users online at the same time, while by late January 2005 there were regularly up to 1.8 million users online at the same time. The software has been downloaded over 64 million times.

Skype has established partnerships with online web properties including Tom.com, PcHomeOnline, Daum and Livedoor as well as hardware manufacturers including Plantronics, Logitech, VTech, RTX and Siemens. Another boost to the distribution of Skype came in November 2004 when Kazaa bundled Skype with version 3.0 of its software.

See also

• Comparison of instant messengers

External links

• Official site (http://www.skype.com)
• Official Skype Discussion forums (http://forum.skype.com/bb/)
• SAM - Skype Answering Machine (http://www.freewebs.com/skypeansweringmachine/)
• Opinion piece advocating Skype and similar technologies (http://www.webcogs.com/the_future_of_phone_calls_is_now.aspx)
• An Analysis of the Skype Peer-to-Peer Internet Telephony Protocol (http://arxiv.org/abs/cs.NI/0412017)
• SomeoneNew.com - Skype Dating site - search for Skype users with common interests (http://www.someonenew.com)
• Jyve.com - Portal to Everything Skype - Community, Language Learning, Yellow Pages (http://www.Jyve.com)
• Skype-Sex.com - "Sex Skypin or Skypin for Sex" - Network for Cybersex & more using Skype (http://www.skype-sex.com)

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