First released in August 2003, Skype was created by the Swede Niklas Zennström and the Dane Janus Friis, in cooperation with Ahti Heinla, Priit Kasesalu, and Jaan Tallinn, Estonians who developed the backend that was also used in the music-sharing application Kazaa.[19] In September 2005, eBay acquired Skype for $2.6 billion.[20] In September 2009,[21] Silver Lake, Andreessen Horowitz and the Canada Pension Plan Investment Board announced the acquisition of 65% of Skype for $1.9 billion from eBay, which attributed to the enterprise a market value of $2.92 billion. Microsoft bought Skype in May 2011 for $8.5 billion. Its Skype division headquarters are in Luxembourg, but most of the development team and 44% of all the division's employees are still situated in Tallinn and Tartu, Estonia.Skype allows users to communicate over the Internet by voice using a microphone, by video by using a webcam, as well as with instant messaging. Skype-to-Skype calls to other users are free of charge, while calls to landline telephones and mobile phones (over traditional telephone networks) are charged via a debit-based user account system called Skype Credit. Some network administrators have banned Skype on corporate, government, home, and education networks,[25] citing such reasons as inappropriate usage of resources, excessive bandwidth usage, and security concerns.The Online Number, a.k.a. SkypeIn, service allows Skype users to receive calls on their computers dialed by conventional phone subscribers to a local Skype phone number; local numbers are available for Australia, Belgium, Brazil, Chile, Colombia, Denmark, the Dominican Republic, Estonia, Finland, France, Germany, Hong Kong, Hungary, Ireland, Japan, Mexico, Nepal, New Zealand, Poland, Romania, South Africa, South Korea, Sweden, Switzerland, Turkey, the Netherlands, the United Kingdom, and the United States.[43][44] A Skype user can have local numbers in any of these countries, with calls to the number charged at the same rate as calls to fixed lines in the country. The countries on this growing list are referred to collectively as the SkypeIn Countries.
Skype was claimed initially to be a secure communication, with one of its early web pages stating "highly secure with end-to-end encryption".[115] Security services were invisible to the user, and encryption cannot be disabled. Skype reportedly uses publicly documented, widely trusted encryption techniques: RSA for key negotiation and the Advanced Encryption Standard to encrypt conversations.[116] However, it is impossible to verify that these algorithms are used correctly, completely, and at all times, as there is no public review possible without a protocol specification and/or the program source code. Skype provides an uncontrolled registration system for users with no proof of identity. Instead, a free choice of nicknames permits users to use the system without revealing their identities to other users. It is trivial to set up an account using any name; the displayed caller's name is no guarantee of authenticity. A third-party paper analyzing the security and methodology of Skype was presented at Black Hat Europe 2006. It analyzed Skype and found a number of security issues with the then-current security model.In an interview, Kurt Sauer, the Chief Security Officer of Skype, said, "We provide a safe communication option. I will not tell you whether we can listen or not."[119] This does not deny the fact that the NSA monitors Skype conversations. Skype's client uses an undocumented and proprietary protocol. The Free Software Foundation (FSF) is concerned about user privacy issues arising from using proprietary software and protocols and has made a replacement for Skype one of their high-priority projects.[120] Security researchers Biondi and Desclaux have speculated that Skype may have a back door, since Skype sends traffic even when it is turned off and because Skype has taken extreme measures to obfuscate their traffic and functioning of their program.[121] Several media sources reported that at a meeting about the "Lawful interception of IP based services" held on 25 June 2008, high-ranking unnamed officials at the Austrian interior ministry said that they could listen in on Skype conversations without problems. Austrian public broadcasting service ORF, citing minutes from the meeting, reported that "the Austrian police are able to listen in on Skype connections". Skype declined to comment on the reports.[122][123] One easily demonstrated method of monitoring is to set up two computers with the same Skype user ID and password. When a message is typed or a call is received on one computer, the second computer duplicates the audio and text. This requires knowledge of the user ID and password.
Skype was claimed initially to be a secure communication, with one of its early web pages stating "highly secure with end-to-end encryption".[115] Security services were invisible to the user, and encryption cannot be disabled. Skype reportedly uses publicly documented, widely trusted encryption techniques: RSA for key negotiation and the Advanced Encryption Standard to encrypt conversations.[116] However, it is impossible to verify that these algorithms are used correctly, completely, and at all times, as there is no public review possible without a protocol specification and/or the program source code. Skype provides an uncontrolled registration system for users with no proof of identity. Instead, a free choice of nicknames permits users to use the system without revealing their identities to other users. It is trivial to set up an account using any name; the displayed caller's name is no guarantee of authenticity. A third-party paper analyzing the security and methodology of Skype was presented at Black Hat Europe 2006. It analyzed Skype and found a number of security issues with the then-current security model.In an interview, Kurt Sauer, the Chief Security Officer of Skype, said, "We provide a safe communication option. I will not tell you whether we can listen or not."[119] This does not deny the fact that the NSA monitors Skype conversations. Skype's client uses an undocumented and proprietary protocol. The Free Software Foundation (FSF) is concerned about user privacy issues arising from using proprietary software and protocols and has made a replacement for Skype one of their high-priority projects.[120] Security researchers Biondi and Desclaux have speculated that Skype may have a back door, since Skype sends traffic even when it is turned off and because Skype has taken extreme measures to obfuscate their traffic and functioning of their program.[121] Several media sources reported that at a meeting about the "Lawful interception of IP based services" held on 25 June 2008, high-ranking unnamed officials at the Austrian interior ministry said that they could listen in on Skype conversations without problems. Austrian public broadcasting service ORF, citing minutes from the meeting, reported that "the Austrian police are able to listen in on Skype connections". Skype declined to comment on the reports.[122][123] One easily demonstrated method of monitoring is to set up two computers with the same Skype user ID and password. When a message is typed or a call is received on one computer, the second computer duplicates the audio and text. This requires knowledge of the user ID and password.
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