Как правильно пишется скайп

This article is about the software. For the subsidiary company that develops it, see Skype Technologies. For the enterprise application formerly known as Microsoft Lync, see Skype for Business.

Skype

Logo of Skype (2019–present)
Screenshot of Skype version 8 (14.32.55.0) for Windows desktop on Windows 10 in dark mode
Original author(s)	Priit Kasesalu and Jaan Tallinn
Developer(s)	Skype Technologies (Microsoft)
Initial release	29 August 2003; 19 years ago
Stable release(s) [±]
Windows, UWP 15.88.401.0 / 1 September 2022; 4 months ago[1] Windows, desktop 8.89.0.403 / 6 October 2022; 3 months ago[1] macOS 8.88.0.401 / 1 September 2022; 4 months ago[1] Linux 8.88.0.401 / 1 September 2022; 4 months ago[1] Android 8.88.0.404 / 1 September 2022; 4 months ago[2] iOS 8.88.0.404 / 1 September 2022; 4 months ago[3] (iPhone),[4] (iPad)
Operating system	Windows, macOS, Linux, Android, iOS, iPadOS, HoloLens, Xbox One, Xbox Series X/S
Available in	108 languages[5]
Type	Videoconferencing, VoIP and Instant messaging
License	Proprietary software
Website	skype.com

Skype () is a proprietary telecommunications application operated by Skype Technologies, a division of Microsoft, best known for VoIP-based videotelephony, videoconferencing and voice calls. It also has instant messaging, file transfer, debit-based calls to landline and mobile telephones (over traditional telephone networks), and other features. Skype is available on various desktop, mobile, and video game console platforms.

Skype was created by Niklas Zennström, Janus Friis, and four Estonian developers and first released in August 2003. In September 2005, eBay acquired Skype for $2.6 billion.^[6] In September 2009,^[7] Silver Lake, Andreessen Horowitz, and the Canada Pension Plan Investment Board bought 65% of Skype for $1.9 billion from eBay, valuing the business at $2.92 billion. In May 2011, Microsoft bought Skype for $8.5 billion and used it to replace their Windows Live Messenger. As of 2011, most of the development team and 44% of all the division’s employees were in Tallinn and Tartu, Estonia.^[8][9][10]

Skype originally featured a hybrid peer-to-peer and client–server system.^[11] It became entirely powered by Microsoft-operated supernodes in May 2012;^[12] in 2017, it changed from a peer-to-peer service to a centralized Azure-based service.

As of March 2020, Skype was used by 100 million people at least once a month and by 40 million people each day.^[13] During the COVID-19 pandemic, Skype lost a large part of its market share to Zoom.^[14]

Etymology

The name for the software is derived from «Sky peer-to-peer», which was then abbreviated to «Skyper». However, some of the domain names associated with «Skyper» were already taken.^[15] Dropping the final «r» left the current title «Skype», for which domain names were available.^[16]

History

Skype was founded in 2003 by Niklas Zennström, from Sweden, and Janus Friis, from Denmark.^[17] The Skype software was created by Estonians Ahti Heinla, Priit Kasesalu, Jaan Tallinn, and Toivo Annus.^[18] Friis and Annus are credited with the idea of reducing the cost of voice calls by using a P2P protocol like that of Kazaa.^[19] An early alpha version was created and tested in spring 2003, and the first public beta version was released on 29 August 2003.^[20][19]

In June 2005, Skype entered an agreement with the Polish web portal Onet.pl for an integrated offering on the Polish market.^[21] On 12 September 2005, eBay Inc. agreed to acquire Luxembourg-based Skype Technologies SA for approximately US$2.5 billion in up-front cash and eBay stock, plus potential performance-based consideration.^[22] On 1 September 2009, eBay announced it was selling 65% of Skype to Silver Lake, Andreessen Horowitz, and the Canada Pension Plan Investment Board for US$1.9 billion, valuing Skype at US$2.75 billion.^[23] On 14 July 2011, Skype partnered with Comcast to bring its video chat service to Comcast subscribers via HDTV sets.^[24]

On 17 June 2013, Skype released a free video messaging service, which can be operated on Windows, Mac OS, iOS, iPadOS, Android, and BlackBerry.^[25]

Between 2017 and 2020, Skype collaborated with PayPal to provide a money-send feature. It allowed users to transfer funds via the Skype mobile app in the middle of a conversation.^[26]

In 2019, Skype was announced to be the sixth most downloaded mobile app of the decade, from 2010 to 2019.^[27]

Microsoft acquisition

On 10 May 2011, Microsoft Corporation acquired Skype Communications, S.à r.l for US$8.5 billion.^[28] The company was incorporated as a division of Microsoft, which acquired all its technologies with the purchase. The acquisition was completed on 13 October 2011.^[28][29] Shortly after the acquisition, Microsoft began integrating the Skype service with its own products. Along with taking over the development of existing Skype desktop and mobile apps, the company developed a dedicated client app for its then-newly released, touch-focused Windows 8 and Windows RT operating systems. They were made available from Windows Store when the then-new OS launched on 26 October 2012. The following year, it became the default messaging app for Windows 8.1, replacing the Windows 8 Messaging app at the time, and became pre-installed software on every device that came with or upgraded to 8.1.^[30]

In a month-long transition from 8 to 30 April 2013, Microsoft discontinued two^{[see talk]} of its own products in favor of Skype, including its Windows Live Messenger instant messaging service, although Messenger continued to be available in mainland China.^[31][32]

On 11 November 2014, Microsoft announced that in 2015, its Lync product would be replaced by Skype for Business. This combined features of Lync and the consumer Skype software. There are two user interfaces, organizations could switch their users between the default Skype for Business interface to the Lync interface.^[33]

Post-acquisition

On 12 August 2013, Skype released the 4.10 update to the app for Apple iPhone and iPad that allows HD quality video for iPhone 5 and fourth-generation iPads.^[34]

On 20 November 2014, Microsoft Office’s team announced that a new chat powered by Skype would be implemented in their software, giving tools to be able to chat with co-workers in the same document.^[35]

On 15 September 2015, Skype announced the release of Mojis, «a brand new way to express yourself on Skype». Mojis are short clips/gifs featuring characters from films and TV shows to be entered into conversations with the same ease as emoticons. They worked with Universal Studios, Disney Muppets, BBC and other studios to add to the available collection of Mojis.^[36] Later that year, Gurdeep Singh Pall, Corporate Vice President of Skype, announced that Microsoft had acquired the technology from Talko.^[37]

In July 2016, Skype introduced an early Alpha version of a new Skype for Linux client, built with WebRTC technology, after several petitions had asked Microsoft to continue development for Linux.^[38][39] In September of that year, Skype updated their iOS app with new features, including an option to call contacts on Skype through Siri voice commands.^[40] In October of that year, Microsoft launched Skype for Business for Mac.^[41]

In February 2017, Microsoft announced plans to discontinue its Skype Wi-Fi service globally. The application was delisted, and the service itself became non-functional from 31 March 2017.^[42][43] On 5 June 2017, Microsoft announced its plans to revamp Skype with similar features to Snapchat, allowing users to share temporary copies of their photos and video files.^[44] In late June 2017, Microsoft rolled out their latest update for iOS, incorporating a revamped design and new third-party integrations, with platforms including Gfycat, YouTube, and UpWorthy.^[45] It was not well-received, with numerous negative reviews and complaints that the new client broke existing functionality.^[46] Skype later removed this «makeover». In December 2017, Microsoft added «Skype Interviews», a shared code editing system for those wishing to hold job interviews for programming roles.^[47][48]

Microsoft eventually moved the service from a peer-to-peer to a central server based system, and with it adjusted the user interfaces of apps to make text-based messaging more prominent than voice calling. Skype for Windows,^[49] iOS,^[50] Android,^[51] Mac^[52] and Linux^[53] all received significant visual overhauls at this time.

Features

Registered users of Skype are identified by a unique Skype ID and may be listed in the Skype directory under a Skype username.^[54] Skype allows these registered users to communicate through both instant messaging and voice chat. Voice chat allows telephone calls between pairs of users and conference calling and uses proprietary audio codec. Skype’s text chat client allows group chats, emoticons, storing chat history, and editing of previous messages. Offline messages were implemented in a beta build of version 5 but removed after a few weeks without notification. The usual features familiar to instant messaging users—user profiles, online status indicators, and so on—are also included.

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, India, Ireland, Japan, Mexico, Nepal, New Zealand, Poland, Romania, South Africa, South Korea, Sweden, Switzerland, Turkey, the Netherlands, the United Kingdom, and the United States.^[55][56] 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.

Skype supports conference calls, video chats, and screen sharing between 25 people at a time for free,^[57] which then increased to 50 on 5 April 2019.^[58]

Skype does not provide the ability to call emergency numbers, such as 112 in Europe, 911 in North America, 999 in the UK or 100 in India and Nepal.^[59] However, as of December 2012, there is limited support for emergency calls in the United Kingdom, Australia, Denmark, and Finland.^[60] The U.S. Federal Communications Commission (FCC) has ruled that, for the purposes of section 255 of the Telecommunications Act, Skype is not an «interconnected VoIP provider».^[61] As a result, the U.S. National Emergency Number Association recommends that all VoIP users have an analog line available as a backup.^[62]

In 2019, Skype added an option to blur the background in a video chat interface using AI algorithms purely done using software, despite a depth-sensing camera not being present in most webcams.^[63]

Usage and traffic

This section needs to be updated. Please help update this article to reflect recent events or newly available information. (February 2020)

Usage and traffic
Date	Total user accounts (millions) [64][65][66][67][68][69][70]	Active users, daily use (millions) [71][72][73]	Skype to Skype minutes (billions) [74]	SkypeOut minutes (billions)	Revenue USD (millions)
Q4 2005	74.7	10.8	—	—	—
Q1 2006	94.6	15.2	6.9	0.7	35
Q2 2006	113.1	16.6	7.1	0.8	44
Q3 2006	135.9	18.7	6.6	1.1	50
Q4 2006	171.2	21.2	7.6	1.5	66
Q1 2007	195.5	23.2	7.7	1.3	79
Q2 2007	219.6	23.9	7.1	1.3	90
Q3 2007	245.7	24.2	6.1	1.4	98
Q4 2007	276.3	27.0	11.9	1.6	115
Q1 2008	309.3	31.3	14.2	1.7	126
Q2 2008	338.2	32.0	14.8	1.9	136
Q3 2008	370	33.7	16.0	2.2	143
Q4 2008	405	36.5	20.5	2.6	145
Q1 2009	443	42.2	23.6	2.9	153
Q2 2009	483	?	25.5	3.0	170
Q3 2009	521	?	27.7	3.1	185
Q4 2009	560	?	36.1	?	?
Q1 2010	?	?	190	12.8	860
Q2 2010	?	?	?	?	?
Q3 2010	?	?	?	?	?
Q4 2010	?	?	?	?	?
Q1 2011	?	?	?	?	?
Q2 2011	?	?	?	?	?
Q3 2011	663	?	?	?	?
Q4 2011	?	?	?	?	?
Q1 2012	?	?	?	?	?
Q2 2012	?	?	?	?	?
Users may have more than one account; it is not possible to count users, only accounts. The volume of international traffic routed via Skype is significant. In 2009 it was considered the largest international voice carrier (by minutes of calls).[75]

Year	International call market share
2005	2.9%[76]
2006	4.4%[76]
2008	8%[75]
2009	12%[74]
2010	13%[77]
2012	33%[78]
2013	36%[79]
2014	40%[80]

At the end of 2010, there were over 660 million worldwide users, with over 300 million estimated active each month as of August 2015.^[81] At one point in February 2012, there were 34 million users concurrently online on Skype.^[82]

In January 2011, after the release of video calling on the Skype client for iPhone, Skype reached a record 27 million simultaneous online users.^[83] This record was broken with 29 million simultaneous online users on 21 February 2011^[84] and again on 28 March 2011 with 30 million online users.^[85] On 25 February 2012, Skype announced that it has over 32 million users for the first time ever.^[86] By 5 March 2012, it had 36 million simultaneous online users,^[87] and less than a year later, on 21 January 2013, Skype had more than 50 million concurrent users online.^[88]
In June 2012, Skype had surpassed 70 million downloads on Android.^[89]

On 19 July 2012, Microsoft announced that Skype users had logged 115 billion minutes of calls in the quarter, up to 50% since the last quarter.^[90]

On 15 January 2014, TeleGeography estimated that Skype-to-Skype international traffic has gone up to 36% in 2013 to 214 billion minutes.^[91]

At end March 2020 there was a 70% increase in the number of daily users from the previous month, due to the COVID-19 pandemic.^[92]

System and software

Client applications and devices

Windows client

Multiple different versions of Skype have been released for Windows since its conception. The original line of Skype applications continued from versions 1.0 through 4.0. It has offered a desktop-only program since 2003. Later, a mobile version was created for Windows Phones.

In 2012, Skype introduced a new version for Windows 8 similar to the Windows Phone version.^[93] On 7 July 2015 Skype modified the application to direct Windows users to download the desktop version, but it was set to continue working on Windows RT until October 2016.^[94] In November 2015, Skype introduced three new applications, called Messaging, Skype Video, and Phone, intended to provide an integrated Skype experience on Windows 10.^[95][96] On 24 March 2016, Skype announced the integrated applications did not satisfy most users’ needs and announced that they and the desktop client would eventually be replaced with a new UWP application,^[97] which was released as a preview version for the Windows 10 Anniversary Update and dubbed as the stable version with the release of the Windows 10 Creators Update.

The latest version of Skype for Windows is Skype 11, which is based on the Universal Windows Platform and runs on various Windows 10-related systems, including Xbox One, Xbox Series X/S, Windows phones, and Microsoft Hololens. Microsoft still offers the older Skype 8, which is Win32-based and runs on all systems from Windows XP (which is otherwise unsupported by Microsoft) to the most recent release of Windows 10.^[98]

In late 2017, this version was upgraded to Skype 12.9 in which several features were both removed and added.^[99]

Other desktop clients

• macOS (10.9 or newer)^[98]
• Linux (Debian, Debian-based (Ubuntu, etc.), Fedora, openSUSE)^[98]

Mobile clients

• iOS
• Android

Skype was previously available on Nokia X, Symbian, BlackBerry OS and BlackBerry 10 devices.
In May 2009 a Version 3.0 was available on Windows Mobile 5 to 6.1, and in September 2015 a Version 2.29^[100] was available on Windows Phone 8.1; in 2016 Microsoft announced that this would stop working in early 2017 once Skype’s transition from peer-to-peer to client-server was complete.^[101]

Other platforms

• The Nokia N800, N810, and N900 Internet tablets, which run Maemo
• The Nokia N9, which runs MeeGo, comes with Skype voice calling and text messaging integrated; however, it lacks video-calling.
• Both the Sony mylo COM-1 and COM-2 models
• The PlayStation Portable Slim and Lite series, though the user needs to purchase a specially designed microphone peripheral. The PSP-3000 has a built-in microphone, which allows communication without the Skype peripheral.^[102] The PSP Go has the ability to use Bluetooth connections with the Skype application, in addition to its built-in microphone.^[103] Skype for PlayStation Vita may be downloaded via the PlayStation Network in the U.S. It includes the capability to receive incoming calls with the application running in the background.
• The Samsung Smart TV had a Skype app, which could be downloaded for free.^[104] It used the built-in camera and microphone for the newer models. Alternatively, a separate mountable Skype camera with built-in speakers and microphones is available to purchase for older models.^[105] This functionality has now been disabled along with any other «TV Based» Skype clients.
• Some devices were made to work with Skype by talking to a desktop Skype client or by embedding Skype software into the device. These were usually either tethered to a PC or have a built-in Wi-Fi client to allow calling from Wi-Fi hotspots, like the Netgear SPH101 Skype Wi-Fi Phone, the SMC WSKP100 Skype Wi-Fi Phone, the Belkin F1PP000GN-SK Wi-Fi Skype Phone, the Panasonic KX-WP1050 Wi-Fi Phone for Skype Executive Travel Set, the IPEVO So-20 Wi-Fi Phone for Skype and the Linksys CIT200 Wi-Fi Phone.

Third-party licensing

Third-party developers, such as Truphone, Nimbuzz, and Fring, previously allowed Skype to run in parallel with several other competing VoIP/IM networks (Truphone and Nimbuzz provide TruphoneOut and NimbuzzOut as a competing paid service) in any Symbian or Java environment. Nimbuzz made Skype available to BlackBerry users and Fring provided mobile video calling over Skype as well as support for the Android platform. Skype disabled access to Skype by Fring users in July 2010.^[106] Nimbuzz discontinued support of Skype on request in October 2010.^[107]

Before and during the Microsoft acquisition, Skype withdrew licensing from several third parties producing software and hardware compatible with Skype. The Skype for Asterisk product from Digium was withdrawn as «no longer available for sale».^[108] The Senao SN358+ long-range (10–15 km) cordless phone was discontinued due to loss of licenses to participate in the Skype network as peers. In combination, these two products made it possible to create roaming cordless mesh networks with a robust handoff.

Technology

Protocol

Skype uses a proprietary Internet telephony (VoIP) network called the Skype protocol. The protocol has not been made publicly available by Skype, and official applications using the protocol are also proprietary. Part of the Skype technology relies on the Global Index P2P protocol belonging to the Joltid Ltd. corporation. The main difference between Skype and standard VoIP clients is that Skype operates on a peer-to-peer model (originally based on the Kazaa software^[109]), rather than the more usual client–server model (note that the very popular Session Initiation Protocol (SIP) model of VoIP is also peer-to-peer, but implementation generally requires registration with a server, as does Skype).

On 20 June 2014, Microsoft announced the deprecation of the old Skype protocol. Within several months from this date, in order to continue using Skype services, Skype users will have to update to Skype applications released in 2014. The new Skype protocol, Microsoft Notification Protocol 24, was released. The deprecation became effective in the second week of August 2014. Transferred files are now saved on central servers.

As far as networking stack support is concerned, Skype only supports the IPv4 protocol. It lacks support for the next-generation Internet protocol, IPv6.^[110] Skype for Business, however, includes support for IPv6 addresses, along with continued support of IPv4.^[111]

Protocol detection and control

Many networking and security companies have claimed to detect and control Skype’s protocol for enterprise and carrier applications. While the specific detection methods used by these companies are often private, Pearson’s chi-squared test and naive Bayes classification are two approaches that were published in 2008.^[112] Combining statistical measurements of payload properties (such as byte frequencies and initial byte sequences) as well as flow properties (like packet sizes and packet directions) has also shown to be an effective method for identifying Skype’s TCP- and UDP-based protocols.^[113]

Audio codecs

Skype 2.x used G.729, Skype 3.2 introduced SVOPC, and Skype 4.0 added a Skype-created codec called SILK, intended to be «lightweight and embeddable».^[114] Additionally, Skype has released Opus as a free codec, which integrates the SILK codec principles for voice transmission with the CELT codec principles for higher-quality audio transmissions, such as live music performances. Opus was submitted to the Internet Engineering Task Force (IETF) in September 2010.^[115] Since then, it has been standardized as RFC 6716.^[116]

Video codecs

VP7 is used for versions prior to Skype 5.5.^{[117][118][119][120][121]}

As of version 7.0, H.264 is used for both group and one-on-one video chat, at standard definition, 720p and 1080p high-definition.^[122][123]

Skype Qik

Skype acquired the video service Qik in 2011. After shutting down Qik in April 2014, Skype relaunched the service as Skype Qik on 14 October 2014. Although Qik offered video conferencing and Internet streaming, the new service focuses on mobile video messaging between individuals and groups.^[124]

Hyperlink format

Skype uses URIs as skype:USER?call for a call.^[125]

Security and privacy

Skype was claimed initially to be a secure communication, with one of its early web pages stating «highly secure with end-to-end encryption».^[126] Security services were invisible to the user, and encryption cannot be disabled. Skype claims to use publicly documented, widely trusted encryption techniques for Skype-to-Skype communication: RSA for key negotiation and the Advanced Encryption Standard to encrypt conversations.^[127] 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’s source code. Skype provides an uncontrolled registration system for users with no proof of identity. Instead, users may choose a screen name which does not have to relate to their real-life identity in any way; a name chosen could also be an impersonation attempt, where the user claims to be someone else for fraudulent purposes. 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.^[128]

Skype incorporates some features that tend to hide its traffic, but it is not specifically designed to thwart traffic analysis and therefore does not provide anonymous communication. Some researchers have been able to watermark the traffic so that it is identifiable even after passing through an anonymizing network.^[130]

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.»^[131] This does not deny the fact that the U.S. National Security Agency (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.^[132] 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 the program’s traffic and functioning.^[133] 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.^[134][135] 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.

The United States Federal Communications Commission (FCC) has interpreted the Communications Assistance for Law Enforcement Act (CALEA) as requiring digital phone networks to allow wiretapping if authorized by an FBI warrant, in the same way as other phone services. In February 2009, Skype said that, not being a telephone company owning phone lines, it is exempt from CALEA and similar laws, which regulate US phone companies, and it is not clear whether Skype could support wiretapping even if it wanted to.^[136] According to the ACLU, the Act is inconsistent with the original intent of the Fourth Amendment to the U.S. Constitution;^[137] more recently, the ACLU has expressed the concern that the FCC interpretation of the Act is incorrect.^[138][139] It has been suggested that Microsoft made changes to Skype’s infrastructure to ease various wiretapping requirements;^[140] however, Skype denies the claims.^[141]

Sometime before Skype was sold in 2009, the company had started Project Chess, a program to explore legal and technical ways to easily share calls with intelligence agencies and law enforcement.^[142]

On 20 February 2009, the European Union’s Eurojust agency announced that the Italian Desk at Eurojust would «play a key role in the coordination and cooperation of the investigations on the use of internet telephony systems (VoIP), such as ‘Skype’. […] The purpose of Eurojust’s coordination role is to overcome the technical and judicial obstacles to the interception of internet telephony systems, taking into account the various data protection rules and civil rights.»^[143]

In November 2010, a flaw was disclosed to Skype that showed how computer crackers could secretly track any user’s IP address.^[144] Due to Skype’s peer-to-peer nature, this was a difficult issue to address, but this bug was eventually remedied in a 2016 update.^[145]

In 2012, Skype introduced automatic updates to better protect users from security risks but received some challenge from users of the Mac product, as the updates cannot be disabled from version 5.6 on,^[146] both on Mac OS and Windows versions, although in the latter, and only from version 5.9 on, automatic updating can be turned off in certain cases.^[147]

According to a 2012 Washington Post article, Skype «has expanded its cooperation with law enforcement authorities to make online chats and other user information available to police»; the article additionally mentions Skype made changes to allow authorities access to addresses and credit card numbers.^[148]

In November 2012, Skype was reported to have handed over user data of a pro-WikiLeaks activist to Dallas, Texas-based private security company iSIGHT Partners without a warrant or court order. The alleged handover would be a breach of Skype’s privacy policy. Skype responded with a statement that it launched an internal investigation to probe the breach of user data privacy.^[149]

On 13 November 2012, a Russian user published a flaw in Skype’s security, which allowed any person to take over a Skype account knowing only the victim’s email by following seven steps.^[150][151] This vulnerability was claimed to exist for months and existed for more than 12 hours since published widely.

On 14 May 2013, it was documented that a URL sent via a Skype instant messaging session was usurped by the Skype service and subsequently used in a HTTP HEAD query originating from an IP address registered to Microsoft in Redmond (the IP address used was 65.52.100.214). The Microsoft query used the full URL supplied in the IM conversation and was generated by a previously undocumented security service.^[152] Security experts speculate the action was triggered by a technology similar to Microsoft’s SmartScreen Filter used in its browsers.^[153]

The 2013 mass surveillance disclosures revealed that agencies such as the NSA and the FBI have the ability to eavesdrop on Skype, including the monitoring and storage of text and video calls and file transfers.^{[154][155][156]} The PRISM surveillance program, which requires FISA court authorization, reportedly has allowed the NSA unfettered access to its data center supernodes. According to the leaked documents, integration work began in November 2010, but it was not until February 2011 that the company was served with a directive to comply signed by the attorney general,^[154] with NSA documents showing that collection began on 31 March 2011.^[157]

On 10 November 2014, Skype scored 1 out of 7 points on the Electronic Frontier Foundation’s secure messaging scorecard. Skype received a point for encryption during transit but lost points because communications are not encrypted with a key the provider does not have access to (i.e. the communications are not end-to-end encrypted), users cannot verify contacts’ identities, past messages are not secure if the encryption keys are stolen (i.e. the service does not provide forward secrecy), the code is not open to independent review (i.e. not available to merely view, nor under a free-software license), the security design is not properly documented, and there has not been a recent independent security audit.^{[158][159][160]} AIM, BlackBerry Messenger, Ebuddy XMS, Hushmail, Kik Messenger, Viber and Yahoo Messenger also scored 1 out of 7 points.^[158]

As of August 2018, Skype now supports end-to-end encryption across all platforms.^[161]

Cybercrime on application

Cybersex trafficking has occurred on Skype^{[162][163][164][165]} and other videoconferencing applications.^[166] According to the Australian Federal Police, overseas pedophiles are directing child sex abuse using its live streaming services.^[167][165]

Service in the People’s Republic of China

This article’s factual accuracy may be compromised due to out-of-date information. Please help update this article to reflect recent events or newly available information. (January 2012)

Since September 2007, users in China trying to download the Skype software client have been redirected to the site of TOM Online, a joint venture between a Chinese wireless operator and Skype, from which a modified Chinese version can be downloaded.^[168] The TOM client participates in China’s system of Internet censorship, monitoring text messages between Skype users in China as well as messages exchanged with users outside the country.^[169][170] Niklas Zennström, then chief executive of Skype, told reporters that TOM «had implemented a text filter, which is what everyone else in that market is doing. Those are the regulations.» He also stated, «One thing that’s certain is that those things are in no way jeopardising the privacy or the security of any of the users.»^[171]

In October 2008, it was reported that TOM had been saving the full message contents of some Skype text conversations on its servers, apparently focusing on conversations containing political issues such as Tibet, Falun Gong, Taiwan independence, and the Chinese Communist Party. The saved messages contain personally identifiable information about the message senders and recipients, including IP addresses, usernames, landline phone numbers, and the entire content of the text messages, including the time and date of each message. Information about Skype users outside China who were communicating with a TOM-Skype user was also saved. A server misconfiguration made these log files accessible to the public for a time.^{[170][172][173]}

Research on the TOM-Skype venture has revealed information about blacklisted keyword checks, allowing censorship and surveillance of its users. The partnership has received much criticism for the latter. Microsoft remains unavailable for comment on the issue.^[174]

According to reports from the advocacy group Great Fire, Microsoft has modified censorship restrictions and ensured encryption of all user information.^[174] Furthermore, Microsoft is now partnered with Guangming Founder (GMF) in China.^[175]

All attempts to visit the official Skype web page from mainland China redirects the user to skype.gmw.cn. The Linux version of Skype is unavailable.^{[citation needed]}

Localization

Skype comes bundled with the following locales and languages: Arabic, Bulgarian, Catalan, Chinese (Traditional and Simplified), Croatian, Czech, Danish, Dutch, English, Estonian, Finnish, French, German, Greek, Hebrew, Hungarian, Indonesian, Italian, Japanese, Korean, Latvian, Lithuanian, Nepali, Norwegian, Polish, Portuguese (Brazilian and European), Romanian, Russian, Serbian, Slovak, Slovenian, Spanish, Swedish, Thai, Turkish, Ukrainian, and Vietnamese.

As the Windows desktop program offers users the option of creating new language files, at least 80 other (full or partial) localizations are also available for many languages.^[176]

Customer service

In January 2010, Skype rescinded its policy of seizing funds in Skype accounts that have been inactive (no paid call) for 180 days. This was in settlement of a class-action lawsuit.^[177] Skype also paid up to US$4 to persons who opted into the action.

As of February 2012, Skype provides support through their web support portal, support community, @skypesupport on Twitter, and Skype Facebook page. Direct contact via email and live chat is available through their web support portal. Chat Support is a premium feature available to Skype Premium and some other paid users.

Skype’s refund policy states that they will provide refunds in full if customers have used less than 1 euro of their Skype Credit. «Upon a duly submitted request, Skype will refund you on a pro-rata basis for the unused period of a Product».

Skype has come under some criticism from users for the inability to completely close accounts. Users not wanting to continue using Skype can make their account inactive by deleting all personal information, except for the username.^[178]

Due to an outage on 21 September 2015 that affected several users in New Zealand, Australia, and other countries, Skype decided to compensate their customers with 20 minutes of free calls to over 60 landline and 8 mobile phone destinations.^[179]

Educational use

Although Skype is a commercial product, its non-paid version is used with increasing frequency among teachers, schools, and charities interested in global education projects.^[180] A popular use case is to facilitate language learning through conversations that alternate between each participant’s native language.^{[181][182][183][184]}

The video conferencing aspect of the software has been praised for its ability to connect students who speak different languages, facilitate virtual field trips, and engage directly with experts.^[185][186]

Skype in the classroom is another free-of-charge tool that Skype has set up on its website, designed to encourage teachers to make their classrooms more interactive, and collaborate with other teachers around the world. There are various Skype lessons in which students can participate. Teachers can also use a search tool and find experts in a particular field.^[187] The educational program Skype a Scientist, set up by biologist Sarah McAnulty in 2017, had in two years connected 14,312 classrooms with over 7000 volunteer scientists.^[188]

However, Skype is not adopted universally, with many educational institutions in the United States and Europe blocking the application from their networks.^{[citation needed][why?]}

See also

• Caller ID spoofing
• Censorship of Skype
• Comparison of instant messaging clients
• Comparison of instant messaging protocols
• Comparison of VoIP software
• List of video telecommunication services and product brands
• Mobile VoIP
• Presence information
• Unified communications

References

External links

• Official website

This article is about the software. For the subsidiary company that develops it, see Skype Technologies. For the enterprise application formerly known as Microsoft Lync, see Skype for Business.

Skype

Logo of Skype (2019–present)
Screenshot of Skype version 8 (14.32.55.0) for Windows desktop on Windows 10 in dark mode
Original author(s)	Priit Kasesalu and Jaan Tallinn
Developer(s)	Skype Technologies (Microsoft)
Initial release	29 August 2003; 19 years ago
Stable release(s) [±]
Windows, UWP 15.88.401.0 / 1 September 2022; 4 months ago[1] Windows, desktop 8.89.0.403 / 6 October 2022; 3 months ago[1] macOS 8.88.0.401 / 1 September 2022; 4 months ago[1] Linux 8.88.0.401 / 1 September 2022; 4 months ago[1] Android 8.88.0.404 / 1 September 2022; 4 months ago[2] iOS 8.88.0.404 / 1 September 2022; 4 months ago[3] (iPhone),[4] (iPad)
Operating system	Windows, macOS, Linux, Android, iOS, iPadOS, HoloLens, Xbox One, Xbox Series X/S
Available in	108 languages[5]
Type	Videoconferencing, VoIP and Instant messaging
License	Proprietary software
Website	skype.com

Skype () is a proprietary telecommunications application operated by Skype Technologies, a division of Microsoft, best known for VoIP-based videotelephony, videoconferencing and voice calls. It also has instant messaging, file transfer, debit-based calls to landline and mobile telephones (over traditional telephone networks), and other features. Skype is available on various desktop, mobile, and video game console platforms.

Skype was created by Niklas Zennström, Janus Friis, and four Estonian developers and first released in August 2003. In September 2005, eBay acquired Skype for $2.6 billion.^[6] In September 2009,^[7] Silver Lake, Andreessen Horowitz, and the Canada Pension Plan Investment Board bought 65% of Skype for $1.9 billion from eBay, valuing the business at $2.92 billion. In May 2011, Microsoft bought Skype for $8.5 billion and used it to replace their Windows Live Messenger. As of 2011, most of the development team and 44% of all the division’s employees were in Tallinn and Tartu, Estonia.^[8][9][10]

Skype originally featured a hybrid peer-to-peer and client–server system.^[11] It became entirely powered by Microsoft-operated supernodes in May 2012;^[12] in 2017, it changed from a peer-to-peer service to a centralized Azure-based service.

As of March 2020, Skype was used by 100 million people at least once a month and by 40 million people each day.^[13] During the COVID-19 pandemic, Skype lost a large part of its market share to Zoom.^[14]

Etymology

The name for the software is derived from «Sky peer-to-peer», which was then abbreviated to «Skyper». However, some of the domain names associated with «Skyper» were already taken.^[15] Dropping the final «r» left the current title «Skype», for which domain names were available.^[16]

History

Skype was founded in 2003 by Niklas Zennström, from Sweden, and Janus Friis, from Denmark.^[17] The Skype software was created by Estonians Ahti Heinla, Priit Kasesalu, Jaan Tallinn, and Toivo Annus.^[18] Friis and Annus are credited with the idea of reducing the cost of voice calls by using a P2P protocol like that of Kazaa.^[19] An early alpha version was created and tested in spring 2003, and the first public beta version was released on 29 August 2003.^[20][19]

In June 2005, Skype entered an agreement with the Polish web portal Onet.pl for an integrated offering on the Polish market.^[21] On 12 September 2005, eBay Inc. agreed to acquire Luxembourg-based Skype Technologies SA for approximately US$2.5 billion in up-front cash and eBay stock, plus potential performance-based consideration.^[22] On 1 September 2009, eBay announced it was selling 65% of Skype to Silver Lake, Andreessen Horowitz, and the Canada Pension Plan Investment Board for US$1.9 billion, valuing Skype at US$2.75 billion.^[23] On 14 July 2011, Skype partnered with Comcast to bring its video chat service to Comcast subscribers via HDTV sets.^[24]

On 17 June 2013, Skype released a free video messaging service, which can be operated on Windows, Mac OS, iOS, iPadOS, Android, and BlackBerry.^[25]

Between 2017 and 2020, Skype collaborated with PayPal to provide a money-send feature. It allowed users to transfer funds via the Skype mobile app in the middle of a conversation.^[26]

In 2019, Skype was announced to be the sixth most downloaded mobile app of the decade, from 2010 to 2019.^[27]

Microsoft acquisition

On 10 May 2011, Microsoft Corporation acquired Skype Communications, S.à r.l for US$8.5 billion.^[28] The company was incorporated as a division of Microsoft, which acquired all its technologies with the purchase. The acquisition was completed on 13 October 2011.^[28][29] Shortly after the acquisition, Microsoft began integrating the Skype service with its own products. Along with taking over the development of existing Skype desktop and mobile apps, the company developed a dedicated client app for its then-newly released, touch-focused Windows 8 and Windows RT operating systems. They were made available from Windows Store when the then-new OS launched on 26 October 2012. The following year, it became the default messaging app for Windows 8.1, replacing the Windows 8 Messaging app at the time, and became pre-installed software on every device that came with or upgraded to 8.1.^[30]

In a month-long transition from 8 to 30 April 2013, Microsoft discontinued two^{[see talk]} of its own products in favor of Skype, including its Windows Live Messenger instant messaging service, although Messenger continued to be available in mainland China.^[31][32]

On 11 November 2014, Microsoft announced that in 2015, its Lync product would be replaced by Skype for Business. This combined features of Lync and the consumer Skype software. There are two user interfaces, organizations could switch their users between the default Skype for Business interface to the Lync interface.^[33]

Post-acquisition

On 12 August 2013, Skype released the 4.10 update to the app for Apple iPhone and iPad that allows HD quality video for iPhone 5 and fourth-generation iPads.^[34]

On 20 November 2014, Microsoft Office’s team announced that a new chat powered by Skype would be implemented in their software, giving tools to be able to chat with co-workers in the same document.^[35]

On 15 September 2015, Skype announced the release of Mojis, «a brand new way to express yourself on Skype». Mojis are short clips/gifs featuring characters from films and TV shows to be entered into conversations with the same ease as emoticons. They worked with Universal Studios, Disney Muppets, BBC and other studios to add to the available collection of Mojis.^[36] Later that year, Gurdeep Singh Pall, Corporate Vice President of Skype, announced that Microsoft had acquired the technology from Talko.^[37]

In July 2016, Skype introduced an early Alpha version of a new Skype for Linux client, built with WebRTC technology, after several petitions had asked Microsoft to continue development for Linux.^[38][39] In September of that year, Skype updated their iOS app with new features, including an option to call contacts on Skype through Siri voice commands.^[40] In October of that year, Microsoft launched Skype for Business for Mac.^[41]

In February 2017, Microsoft announced plans to discontinue its Skype Wi-Fi service globally. The application was delisted, and the service itself became non-functional from 31 March 2017.^[42][43] On 5 June 2017, Microsoft announced its plans to revamp Skype with similar features to Snapchat, allowing users to share temporary copies of their photos and video files.^[44] In late June 2017, Microsoft rolled out their latest update for iOS, incorporating a revamped design and new third-party integrations, with platforms including Gfycat, YouTube, and UpWorthy.^[45] It was not well-received, with numerous negative reviews and complaints that the new client broke existing functionality.^[46] Skype later removed this «makeover». In December 2017, Microsoft added «Skype Interviews», a shared code editing system for those wishing to hold job interviews for programming roles.^[47][48]

Microsoft eventually moved the service from a peer-to-peer to a central server based system, and with it adjusted the user interfaces of apps to make text-based messaging more prominent than voice calling. Skype for Windows,^[49] iOS,^[50] Android,^[51] Mac^[52] and Linux^[53] all received significant visual overhauls at this time.

Features

Registered users of Skype are identified by a unique Skype ID and may be listed in the Skype directory under a Skype username.^[54] Skype allows these registered users to communicate through both instant messaging and voice chat. Voice chat allows telephone calls between pairs of users and conference calling and uses proprietary audio codec. Skype’s text chat client allows group chats, emoticons, storing chat history, and editing of previous messages. Offline messages were implemented in a beta build of version 5 but removed after a few weeks without notification. The usual features familiar to instant messaging users—user profiles, online status indicators, and so on—are also included.

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, India, Ireland, Japan, Mexico, Nepal, New Zealand, Poland, Romania, South Africa, South Korea, Sweden, Switzerland, Turkey, the Netherlands, the United Kingdom, and the United States.^[55][56] 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.

Skype supports conference calls, video chats, and screen sharing between 25 people at a time for free,^[57] which then increased to 50 on 5 April 2019.^[58]

Skype does not provide the ability to call emergency numbers, such as 112 in Europe, 911 in North America, 999 in the UK or 100 in India and Nepal.^[59] However, as of December 2012, there is limited support for emergency calls in the United Kingdom, Australia, Denmark, and Finland.^[60] The U.S. Federal Communications Commission (FCC) has ruled that, for the purposes of section 255 of the Telecommunications Act, Skype is not an «interconnected VoIP provider».^[61] As a result, the U.S. National Emergency Number Association recommends that all VoIP users have an analog line available as a backup.^[62]

In 2019, Skype added an option to blur the background in a video chat interface using AI algorithms purely done using software, despite a depth-sensing camera not being present in most webcams.^[63]

Usage and traffic

This section needs to be updated. Please help update this article to reflect recent events or newly available information. (February 2020)

Usage and traffic
Date	Total user accounts (millions) [64][65][66][67][68][69][70]	Active users, daily use (millions) [71][72][73]	Skype to Skype minutes (billions) [74]	SkypeOut minutes (billions)	Revenue USD (millions)
Q4 2005	74.7	10.8	—	—	—
Q1 2006	94.6	15.2	6.9	0.7	35
Q2 2006	113.1	16.6	7.1	0.8	44
Q3 2006	135.9	18.7	6.6	1.1	50
Q4 2006	171.2	21.2	7.6	1.5	66
Q1 2007	195.5	23.2	7.7	1.3	79
Q2 2007	219.6	23.9	7.1	1.3	90
Q3 2007	245.7	24.2	6.1	1.4	98
Q4 2007	276.3	27.0	11.9	1.6	115
Q1 2008	309.3	31.3	14.2	1.7	126
Q2 2008	338.2	32.0	14.8	1.9	136
Q3 2008	370	33.7	16.0	2.2	143
Q4 2008	405	36.5	20.5	2.6	145
Q1 2009	443	42.2	23.6	2.9	153
Q2 2009	483	?	25.5	3.0	170
Q3 2009	521	?	27.7	3.1	185
Q4 2009	560	?	36.1	?	?
Q1 2010	?	?	190	12.8	860
Q2 2010	?	?	?	?	?
Q3 2010	?	?	?	?	?
Q4 2010	?	?	?	?	?
Q1 2011	?	?	?	?	?
Q2 2011	?	?	?	?	?
Q3 2011	663	?	?	?	?
Q4 2011	?	?	?	?	?
Q1 2012	?	?	?	?	?
Q2 2012	?	?	?	?	?
Users may have more than one account; it is not possible to count users, only accounts. The volume of international traffic routed via Skype is significant. In 2009 it was considered the largest international voice carrier (by minutes of calls).[75]

Year	International call market share
2005	2.9%[76]
2006	4.4%[76]
2008	8%[75]
2009	12%[74]
2010	13%[77]
2012	33%[78]
2013	36%[79]
2014	40%[80]

At the end of 2010, there were over 660 million worldwide users, with over 300 million estimated active each month as of August 2015.^[81] At one point in February 2012, there were 34 million users concurrently online on Skype.^[82]

In January 2011, after the release of video calling on the Skype client for iPhone, Skype reached a record 27 million simultaneous online users.^[83] This record was broken with 29 million simultaneous online users on 21 February 2011^[84] and again on 28 March 2011 with 30 million online users.^[85] On 25 February 2012, Skype announced that it has over 32 million users for the first time ever.^[86] By 5 March 2012, it had 36 million simultaneous online users,^[87] and less than a year later, on 21 January 2013, Skype had more than 50 million concurrent users online.^[88]
In June 2012, Skype had surpassed 70 million downloads on Android.^[89]

On 19 July 2012, Microsoft announced that Skype users had logged 115 billion minutes of calls in the quarter, up to 50% since the last quarter.^[90]

On 15 January 2014, TeleGeography estimated that Skype-to-Skype international traffic has gone up to 36% in 2013 to 214 billion minutes.^[91]

At end March 2020 there was a 70% increase in the number of daily users from the previous month, due to the COVID-19 pandemic.^[92]

System and software

Client applications and devices

Windows client

Multiple different versions of Skype have been released for Windows since its conception. The original line of Skype applications continued from versions 1.0 through 4.0. It has offered a desktop-only program since 2003. Later, a mobile version was created for Windows Phones.

In 2012, Skype introduced a new version for Windows 8 similar to the Windows Phone version.^[93] On 7 July 2015 Skype modified the application to direct Windows users to download the desktop version, but it was set to continue working on Windows RT until October 2016.^[94] In November 2015, Skype introduced three new applications, called Messaging, Skype Video, and Phone, intended to provide an integrated Skype experience on Windows 10.^[95][96] On 24 March 2016, Skype announced the integrated applications did not satisfy most users’ needs and announced that they and the desktop client would eventually be replaced with a new UWP application,^[97] which was released as a preview version for the Windows 10 Anniversary Update and dubbed as the stable version with the release of the Windows 10 Creators Update.

The latest version of Skype for Windows is Skype 11, which is based on the Universal Windows Platform and runs on various Windows 10-related systems, including Xbox One, Xbox Series X/S, Windows phones, and Microsoft Hololens. Microsoft still offers the older Skype 8, which is Win32-based and runs on all systems from Windows XP (which is otherwise unsupported by Microsoft) to the most recent release of Windows 10.^[98]

In late 2017, this version was upgraded to Skype 12.9 in which several features were both removed and added.^[99]

Other desktop clients

• macOS (10.9 or newer)^[98]
• Linux (Debian, Debian-based (Ubuntu, etc.), Fedora, openSUSE)^[98]

Mobile clients

• iOS
• Android

Skype was previously available on Nokia X, Symbian, BlackBerry OS and BlackBerry 10 devices.
In May 2009 a Version 3.0 was available on Windows Mobile 5 to 6.1, and in September 2015 a Version 2.29^[100] was available on Windows Phone 8.1; in 2016 Microsoft announced that this would stop working in early 2017 once Skype’s transition from peer-to-peer to client-server was complete.^[101]

Other platforms

• The Nokia N800, N810, and N900 Internet tablets, which run Maemo
• The Nokia N9, which runs MeeGo, comes with Skype voice calling and text messaging integrated; however, it lacks video-calling.
• Both the Sony mylo COM-1 and COM-2 models
• The PlayStation Portable Slim and Lite series, though the user needs to purchase a specially designed microphone peripheral. The PSP-3000 has a built-in microphone, which allows communication without the Skype peripheral.^[102] The PSP Go has the ability to use Bluetooth connections with the Skype application, in addition to its built-in microphone.^[103] Skype for PlayStation Vita may be downloaded via the PlayStation Network in the U.S. It includes the capability to receive incoming calls with the application running in the background.
• The Samsung Smart TV had a Skype app, which could be downloaded for free.^[104] It used the built-in camera and microphone for the newer models. Alternatively, a separate mountable Skype camera with built-in speakers and microphones is available to purchase for older models.^[105] This functionality has now been disabled along with any other «TV Based» Skype clients.
• Some devices were made to work with Skype by talking to a desktop Skype client or by embedding Skype software into the device. These were usually either tethered to a PC or have a built-in Wi-Fi client to allow calling from Wi-Fi hotspots, like the Netgear SPH101 Skype Wi-Fi Phone, the SMC WSKP100 Skype Wi-Fi Phone, the Belkin F1PP000GN-SK Wi-Fi Skype Phone, the Panasonic KX-WP1050 Wi-Fi Phone for Skype Executive Travel Set, the IPEVO So-20 Wi-Fi Phone for Skype and the Linksys CIT200 Wi-Fi Phone.

Third-party licensing

Third-party developers, such as Truphone, Nimbuzz, and Fring, previously allowed Skype to run in parallel with several other competing VoIP/IM networks (Truphone and Nimbuzz provide TruphoneOut and NimbuzzOut as a competing paid service) in any Symbian or Java environment. Nimbuzz made Skype available to BlackBerry users and Fring provided mobile video calling over Skype as well as support for the Android platform. Skype disabled access to Skype by Fring users in July 2010.^[106] Nimbuzz discontinued support of Skype on request in October 2010.^[107]

Before and during the Microsoft acquisition, Skype withdrew licensing from several third parties producing software and hardware compatible with Skype. The Skype for Asterisk product from Digium was withdrawn as «no longer available for sale».^[108] The Senao SN358+ long-range (10–15 km) cordless phone was discontinued due to loss of licenses to participate in the Skype network as peers. In combination, these two products made it possible to create roaming cordless mesh networks with a robust handoff.

Technology

Protocol

Skype uses a proprietary Internet telephony (VoIP) network called the Skype protocol. The protocol has not been made publicly available by Skype, and official applications using the protocol are also proprietary. Part of the Skype technology relies on the Global Index P2P protocol belonging to the Joltid Ltd. corporation. The main difference between Skype and standard VoIP clients is that Skype operates on a peer-to-peer model (originally based on the Kazaa software^[109]), rather than the more usual client–server model (note that the very popular Session Initiation Protocol (SIP) model of VoIP is also peer-to-peer, but implementation generally requires registration with a server, as does Skype).

On 20 June 2014, Microsoft announced the deprecation of the old Skype protocol. Within several months from this date, in order to continue using Skype services, Skype users will have to update to Skype applications released in 2014. The new Skype protocol, Microsoft Notification Protocol 24, was released. The deprecation became effective in the second week of August 2014. Transferred files are now saved on central servers.

As far as networking stack support is concerned, Skype only supports the IPv4 protocol. It lacks support for the next-generation Internet protocol, IPv6.^[110] Skype for Business, however, includes support for IPv6 addresses, along with continued support of IPv4.^[111]

Protocol detection and control

Many networking and security companies have claimed to detect and control Skype’s protocol for enterprise and carrier applications. While the specific detection methods used by these companies are often private, Pearson’s chi-squared test and naive Bayes classification are two approaches that were published in 2008.^[112] Combining statistical measurements of payload properties (such as byte frequencies and initial byte sequences) as well as flow properties (like packet sizes and packet directions) has also shown to be an effective method for identifying Skype’s TCP- and UDP-based protocols.^[113]

Audio codecs

Skype 2.x used G.729, Skype 3.2 introduced SVOPC, and Skype 4.0 added a Skype-created codec called SILK, intended to be «lightweight and embeddable».^[114] Additionally, Skype has released Opus as a free codec, which integrates the SILK codec principles for voice transmission with the CELT codec principles for higher-quality audio transmissions, such as live music performances. Opus was submitted to the Internet Engineering Task Force (IETF) in September 2010.^[115] Since then, it has been standardized as RFC 6716.^[116]

Video codecs

VP7 is used for versions prior to Skype 5.5.^{[117][118][119][120][121]}

As of version 7.0, H.264 is used for both group and one-on-one video chat, at standard definition, 720p and 1080p high-definition.^[122][123]

Skype Qik

Skype acquired the video service Qik in 2011. After shutting down Qik in April 2014, Skype relaunched the service as Skype Qik on 14 October 2014. Although Qik offered video conferencing and Internet streaming, the new service focuses on mobile video messaging between individuals and groups.^[124]

Hyperlink format

Skype uses URIs as skype:USER?call for a call.^[125]

Security and privacy

Skype was claimed initially to be a secure communication, with one of its early web pages stating «highly secure with end-to-end encryption».^[126] Security services were invisible to the user, and encryption cannot be disabled. Skype claims to use publicly documented, widely trusted encryption techniques for Skype-to-Skype communication: RSA for key negotiation and the Advanced Encryption Standard to encrypt conversations.^[127] 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’s source code. Skype provides an uncontrolled registration system for users with no proof of identity. Instead, users may choose a screen name which does not have to relate to their real-life identity in any way; a name chosen could also be an impersonation attempt, where the user claims to be someone else for fraudulent purposes. 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.^[128]

Skype incorporates some features that tend to hide its traffic, but it is not specifically designed to thwart traffic analysis and therefore does not provide anonymous communication. Some researchers have been able to watermark the traffic so that it is identifiable even after passing through an anonymizing network.^[130]

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.»^[131] This does not deny the fact that the U.S. National Security Agency (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.^[132] 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 the program’s traffic and functioning.^[133] 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.^[134][135] 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.

The United States Federal Communications Commission (FCC) has interpreted the Communications Assistance for Law Enforcement Act (CALEA) as requiring digital phone networks to allow wiretapping if authorized by an FBI warrant, in the same way as other phone services. In February 2009, Skype said that, not being a telephone company owning phone lines, it is exempt from CALEA and similar laws, which regulate US phone companies, and it is not clear whether Skype could support wiretapping even if it wanted to.^[136] According to the ACLU, the Act is inconsistent with the original intent of the Fourth Amendment to the U.S. Constitution;^[137] more recently, the ACLU has expressed the concern that the FCC interpretation of the Act is incorrect.^[138][139] It has been suggested that Microsoft made changes to Skype’s infrastructure to ease various wiretapping requirements;^[140] however, Skype denies the claims.^[141]

Sometime before Skype was sold in 2009, the company had started Project Chess, a program to explore legal and technical ways to easily share calls with intelligence agencies and law enforcement.^[142]

On 20 February 2009, the European Union’s Eurojust agency announced that the Italian Desk at Eurojust would «play a key role in the coordination and cooperation of the investigations on the use of internet telephony systems (VoIP), such as ‘Skype’. […] The purpose of Eurojust’s coordination role is to overcome the technical and judicial obstacles to the interception of internet telephony systems, taking into account the various data protection rules and civil rights.»^[143]

In November 2010, a flaw was disclosed to Skype that showed how computer crackers could secretly track any user’s IP address.^[144] Due to Skype’s peer-to-peer nature, this was a difficult issue to address, but this bug was eventually remedied in a 2016 update.^[145]

In 2012, Skype introduced automatic updates to better protect users from security risks but received some challenge from users of the Mac product, as the updates cannot be disabled from version 5.6 on,^[146] both on Mac OS and Windows versions, although in the latter, and only from version 5.9 on, automatic updating can be turned off in certain cases.^[147]

According to a 2012 Washington Post article, Skype «has expanded its cooperation with law enforcement authorities to make online chats and other user information available to police»; the article additionally mentions Skype made changes to allow authorities access to addresses and credit card numbers.^[148]

In November 2012, Skype was reported to have handed over user data of a pro-WikiLeaks activist to Dallas, Texas-based private security company iSIGHT Partners without a warrant or court order. The alleged handover would be a breach of Skype’s privacy policy. Skype responded with a statement that it launched an internal investigation to probe the breach of user data privacy.^[149]

On 13 November 2012, a Russian user published a flaw in Skype’s security, which allowed any person to take over a Skype account knowing only the victim’s email by following seven steps.^[150][151] This vulnerability was claimed to exist for months and existed for more than 12 hours since published widely.

On 14 May 2013, it was documented that a URL sent via a Skype instant messaging session was usurped by the Skype service and subsequently used in a HTTP HEAD query originating from an IP address registered to Microsoft in Redmond (the IP address used was 65.52.100.214). The Microsoft query used the full URL supplied in the IM conversation and was generated by a previously undocumented security service.^[152] Security experts speculate the action was triggered by a technology similar to Microsoft’s SmartScreen Filter used in its browsers.^[153]

The 2013 mass surveillance disclosures revealed that agencies such as the NSA and the FBI have the ability to eavesdrop on Skype, including the monitoring and storage of text and video calls and file transfers.^{[154][155][156]} The PRISM surveillance program, which requires FISA court authorization, reportedly has allowed the NSA unfettered access to its data center supernodes. According to the leaked documents, integration work began in November 2010, but it was not until February 2011 that the company was served with a directive to comply signed by the attorney general,^[154] with NSA documents showing that collection began on 31 March 2011.^[157]

On 10 November 2014, Skype scored 1 out of 7 points on the Electronic Frontier Foundation’s secure messaging scorecard. Skype received a point for encryption during transit but lost points because communications are not encrypted with a key the provider does not have access to (i.e. the communications are not end-to-end encrypted), users cannot verify contacts’ identities, past messages are not secure if the encryption keys are stolen (i.e. the service does not provide forward secrecy), the code is not open to independent review (i.e. not available to merely view, nor under a free-software license), the security design is not properly documented, and there has not been a recent independent security audit.^{[158][159][160]} AIM, BlackBerry Messenger, Ebuddy XMS, Hushmail, Kik Messenger, Viber and Yahoo Messenger also scored 1 out of 7 points.^[158]

As of August 2018, Skype now supports end-to-end encryption across all platforms.^[161]

Cybercrime on application

Cybersex trafficking has occurred on Skype^{[162][163][164][165]} and other videoconferencing applications.^[166] According to the Australian Federal Police, overseas pedophiles are directing child sex abuse using its live streaming services.^[167][165]

Service in the People’s Republic of China

This article’s factual accuracy may be compromised due to out-of-date information. Please help update this article to reflect recent events or newly available information. (January 2012)

Since September 2007, users in China trying to download the Skype software client have been redirected to the site of TOM Online, a joint venture between a Chinese wireless operator and Skype, from which a modified Chinese version can be downloaded.^[168] The TOM client participates in China’s system of Internet censorship, monitoring text messages between Skype users in China as well as messages exchanged with users outside the country.^[169][170] Niklas Zennström, then chief executive of Skype, told reporters that TOM «had implemented a text filter, which is what everyone else in that market is doing. Those are the regulations.» He also stated, «One thing that’s certain is that those things are in no way jeopardising the privacy or the security of any of the users.»^[171]

In October 2008, it was reported that TOM had been saving the full message contents of some Skype text conversations on its servers, apparently focusing on conversations containing political issues such as Tibet, Falun Gong, Taiwan independence, and the Chinese Communist Party. The saved messages contain personally identifiable information about the message senders and recipients, including IP addresses, usernames, landline phone numbers, and the entire content of the text messages, including the time and date of each message. Information about Skype users outside China who were communicating with a TOM-Skype user was also saved. A server misconfiguration made these log files accessible to the public for a time.^{[170][172][173]}

Research on the TOM-Skype venture has revealed information about blacklisted keyword checks, allowing censorship and surveillance of its users. The partnership has received much criticism for the latter. Microsoft remains unavailable for comment on the issue.^[174]

According to reports from the advocacy group Great Fire, Microsoft has modified censorship restrictions and ensured encryption of all user information.^[174] Furthermore, Microsoft is now partnered with Guangming Founder (GMF) in China.^[175]

All attempts to visit the official Skype web page from mainland China redirects the user to skype.gmw.cn. The Linux version of Skype is unavailable.^{[citation needed]}

Localization

Skype comes bundled with the following locales and languages: Arabic, Bulgarian, Catalan, Chinese (Traditional and Simplified), Croatian, Czech, Danish, Dutch, English, Estonian, Finnish, French, German, Greek, Hebrew, Hungarian, Indonesian, Italian, Japanese, Korean, Latvian, Lithuanian, Nepali, Norwegian, Polish, Portuguese (Brazilian and European), Romanian, Russian, Serbian, Slovak, Slovenian, Spanish, Swedish, Thai, Turkish, Ukrainian, and Vietnamese.

As the Windows desktop program offers users the option of creating new language files, at least 80 other (full or partial) localizations are also available for many languages.^[176]

Customer service

In January 2010, Skype rescinded its policy of seizing funds in Skype accounts that have been inactive (no paid call) for 180 days. This was in settlement of a class-action lawsuit.^[177] Skype also paid up to US$4 to persons who opted into the action.

As of February 2012, Skype provides support through their web support portal, support community, @skypesupport on Twitter, and Skype Facebook page. Direct contact via email and live chat is available through their web support portal. Chat Support is a premium feature available to Skype Premium and some other paid users.

Skype’s refund policy states that they will provide refunds in full if customers have used less than 1 euro of their Skype Credit. «Upon a duly submitted request, Skype will refund you on a pro-rata basis for the unused period of a Product».

Skype has come under some criticism from users for the inability to completely close accounts. Users not wanting to continue using Skype can make their account inactive by deleting all personal information, except for the username.^[178]

Due to an outage on 21 September 2015 that affected several users in New Zealand, Australia, and other countries, Skype decided to compensate their customers with 20 minutes of free calls to over 60 landline and 8 mobile phone destinations.^[179]

Educational use

Although Skype is a commercial product, its non-paid version is used with increasing frequency among teachers, schools, and charities interested in global education projects.^[180] A popular use case is to facilitate language learning through conversations that alternate between each participant’s native language.^{[181][182][183][184]}

The video conferencing aspect of the software has been praised for its ability to connect students who speak different languages, facilitate virtual field trips, and engage directly with experts.^[185][186]

Skype in the classroom is another free-of-charge tool that Skype has set up on its website, designed to encourage teachers to make their classrooms more interactive, and collaborate with other teachers around the world. There are various Skype lessons in which students can participate. Teachers can also use a search tool and find experts in a particular field.^[187] The educational program Skype a Scientist, set up by biologist Sarah McAnulty in 2017, had in two years connected 14,312 classrooms with over 7000 volunteer scientists.^[188]

However, Skype is not adopted universally, with many educational institutions in the United States and Europe blocking the application from their networks.^{[citation needed][why?]}

See also

• Caller ID spoofing
• Censorship of Skype
• Comparison of instant messaging clients
• Comparison of instant messaging protocols
• Comparison of VoIP software
• List of video telecommunication services and product brands
• Mobile VoIP
• Presence information
• Unified communications

References

External links

• Official website

Эта статья о программном обеспечении; об одноимённой компании см.: Skype Limited.

Skype

Тип	VoIP-сервис, софтфон, IM
Разработчик	Microsoft (ранее Skype Limited)
Написана на	CodeGear Delphi / Objective-C (Mac OS X/iPhone/Nintendo DSi) / C++ с Qt4 (Linux)
Операционная система	Кроссплатформенное программное обеспечение
Последняя версия	1.2[1] Windows 8 6.0.0.126[2] — 14 ноября 2012 (Windows), 4.1.0.20[3] — (Linux x86), 6.0.0.2968[4] — 15 ноября 2012 (Mac OS X) 3.0.0.6181 20 ноября 2012 (Android) 4.2.1 28 ноября 2012 (iOS) 2.0.0.6 — 21 апреля 2011 (Symbian³) 2.0.0.473 — 11 ноября 2012 (Windows Phone
Состояние	В активной разработке
Лицензия	Freeware
Сайт	skype.com

Skype (МФА: [skaɪp]) — бесплатное проприетарное программное обеспечение с закрытым кодом, обеспечивающее шифрованную голосовую связь и видеосвязь через Интернет между компьютерами (VoIP), используя технологии пиринговых сетей, а также платные услуги для звонков на мобильные и стационарные телефоны. Skype имеет 663 миллиона пользователей по состоянию на сентябрь 2011 года. Большинство разработчиков и 44 % работников общего отдела находятся в Таллине и Тарту, Эстония.

Некоторые сетевые администраторы запретили использование Skype в корпоративных, правительственных, домашних и образовательных сетях, ссылаясь на причины ненадлежащего использования ресурсов, чрезмерной пропускной способности и проблем безопасности.

Программа также позволяет совершать конференц-звонки (до 25 голосовых абонентов, включая инициатора), видеозвонки (в том числе видеоконференции до 10 абонентов), а также обеспечивает передачу текстовых сообщений (чат) и передачу файлов. Есть возможность вместо изображения с веб-камеры передавать изображение с экрана монитора.^[5]

Программные клиенты Skype выпущены для Windows, Mac OS X, Linux, iOS, Windows Phone 7, Windows Phone 8(ознакомительная версия), HP webOS, Android, PSP, PlayStation Vita, Symbian.^[6] Также была выпущена версия для Java.

История

Скайп был создан в 2003 году шведами Никласом Зеннстремом и Янусом Фриисом^[7]. В создании основного кода программы участвовали эстонские программисты Ахти Хейнла (англ. Ahti Heinla), Прийт Казесалу (эст. Priit Kasesalu) и Яан Таллинн (англ. Jaan Tallinn), создавшие ранее программу для файлообмена KaZaA.^[8][9][10]

Первые версии программы (0.97, 0.98) появились в сентябре-октябре 2003 года на сайте, декларирующем себя как шведский. Программа имела простой интерфейс, изначально адаптированный под голосовую связь, в отличие от мессенджеров вроде ICQ и MSN Messenger. Skype при инсталляции сам выбирал язык локализации Windows и имел более простую и быструю регистрацию логина, нежели в конкурирующих программах. Именно простота установки, освоения и использования программы быстро привлекли к ней внимание большого числа пользователей.

В версии 1.2 впервые появился автоответчик (Voicemail), а начиная с версии 1.3 любой его владелец мог оставить сообщения другим пользователям, даже если они не использовали эту услугу. В версии 1.2 также появилась функция SkypeIn, позволяющая связать учётную запись Skype с телефонным номером.

Начиная с версии 1.4, появилась возможность перенаправления звонков на другие учётные записи Skype, а также на обычные телефоны.

В версии 2.0 впервые появилась возможность видеосвязи, а в 2.5 — возможность отправки SMS, организации SkypeCast (эта технология официально отключена с 1 сентября 2008 года) и интеграции с Microsoft Outlook.

В версии 3 появился сервис SkypeFind, который позволяет пользователям создавать список фирм и давать к ним описание. Сейчас он в немалой степени заполнен спамом.

2007

• март: релиз Skype 3.1, добавлены новые возможности, в том числе Skype Find и Skype Prime. Также стала доступна Skype 3.2 beta с новыми возможностями, которые позволяют отправлять деньги через PayPal другим пользователям.
• август: вышел Skype 3.5 для Windows, теперь есть поддержка видео в профайле, а также возможность вставлять видео в чат; трансфер звонка другому пользователю или группе; автоповтор вызова.
• 15 августа: Skype 2.7.0.49 (beta) для Mac OS.

2008

• 30 января: вышла версия Skype для Sony PSP.
• 13 марта: выпущен Skype 2.0 для Linux с поддержкой видеоконференций.
• 9 июля: вышла Skype 4.0 Beta, в четвёртой версии новый интерфейс программы.
• 1 сентября: закрыт сервис SkypeCast.
• 12 сентября: в безлимитном тарифе Unlimited Europe помимо звонков на городские телефоны 21-й европейской страны включены Санкт-Петербург и Москва.
• 26 Декабря: вышла версия Skype 1.0.0 для Nokia Nst-4 в систем-пак v1.0.0.

2009

• 3 февраля: релиз Skype 4.0 (Windows).
• 31 марта: вышла версия Skype для iPhone.^[11]
• 12 мая: прекращена поддержку конференций.
• 9 ноября: выпущена панель инструментов для MS Outlook^[12]

2010

• 19 января: улучшилось качество передачи звука за счёт технологий российской компании SPIRIT в области IP-телефонии.^[13]
• 19 февраля: прекращена поддержка Skype Lite (Skype для Java-телефонов) и Skype для Windows Mobile.^[14]
• 2 сентября: добавлена поддержка офлайн-сообщений в чате.^[15]
• 5 октября: выход полноценного клиента Skype для Android.^[16]
• 14 октября: вышла Skype 5.0 (Windows), в пятой версии новый интерфейс программы и добавлена возможность совершать групповые видеозвонки.^[17]

2011

• 1 января: выходит версия Skype для iPhone и iPod touch c поддержкой видео.^[18]
• 4 апреля: выходит новая версия Skype для Linux.^[19]
• 16 июня: вышла Skype 5.3 (Windows), в новой версии программы появилась интеграция с Facebook через чат программы.
• 1 сентября: в обновлённой версии 5.5 появились HD-смайлы.
• 13 сентября: обновление Skype с 5.5.113 до 5.5.117, в которой осуществлена поддержка Windows 8.^[20]
• 15 сентября: В бета версии программы для Mac OS X введена интеграция с Facebook.

2012

• 27 февраля: выходит бета-версия приложения Skype для пользователей Windows Phone 7 c поддержкой видео в сетях 3G, 4G и Wi-Fi.^[21] Официальная версия приложения доступна в Windows Phone Marketplace с 23 апреля.^[22]
• 25 апреля: выходит Skype для PlayStation Vita.
• 14 июня: выходит Skype 4.0 для Linux-систем.^[23]
• 13 сентября: Skype переходит на аудиокодек Opus с «кристально чистым звуком».^[24]
• 24 октября: Выходит версия 6.0 в которой можно входить, используя логин и пароль от социальной сети Facebook или от сервисов Microsoft.^[25]
• 29 октября: Skype выпускает специальную версию программы для Windows 8
• 11 ноября: Выпускается ознакомительная версия для платформы Windows Phone 8.^[26]

• 13 ноября: Skype выпускает новую версию для iOS, которая поддерживает iPhone 5^[27]

• 15 ноября: На свет появляется версия 4.1.0.20 для Linux. В данной версии добавили возможность объединения аккаунта Skype с аккаунтом в Microsoft^[28]

• 20 ноября: Выпускается Skype 3.0 для Android, в которой так же добавлена возможность объединение аккаунта Skype и Microsoft

• 28 ноября: Доступна для загрузки версия 4.2.1 для iOS в которой добавлена возможность использования смайлов

Оборот и статистика

Информация в этой статье или некоторых её разделах устарела. Вы можете помочь проекту, обновив её и убрав после этого данный шаблон.

Год	Квартал	Учётных записей, млн[29][30][31][32][33][34]	Пользователей в сети, млн[источник не указан 488 дней]	Звонков внутри Skype, млрд минут	Звонков SkypeOut, млрд минут	Доход, млн долл.
2005	IV	74,7	10,8	—	—	—
2006	I	94,6	15,2	6,9	0,7	35
2006	II	113,1	16,6	7,1	0,8	44
2006	III	135,9	18,7	6,6	1,1	50
2006	IV	171,2	21,2	7,6	1,5	66
2007	I	195,5	23,2	7,7	1,3	79
2007	II	219,6	23,9	7,1	1,3	90
2007	III	245,7	24,2	6,1	1,4	98
2007	IV	276,3	27,0	11,9	1,6	115
2008	I	309,3	31,3	14,2	1,7	126
2008	II	338,2	32,0	14,8	1,9	136
2008	III	370	33,7	16	2,2	143
2008	IV	405	36,5	20,5	2,6	145
2009	I	443	42,2	23,6	2,9	153
2009	II	483	—	25,5	3,0	170
2009	III	521	—	27,7	3,1	185
2009	IV	560

Один пользователь может иметь более одной учётной записи.

Объём международных голосовых звонков через Skype является значительным. Он стал лидером по трафику голосовых звонков.^[35]

Год	Объём международного рынка голосовых звонков
2005	2,9 %[36]
2006	4,4 %[36]
2008	8 %[35]
2010	13 %[37]

Технология

В отличие от многих других программ IP-телефонии, для передачи данных Skype использует P2P-архитектуру. Каталог пользователей Skype распределён по компьютерам пользователей сети Skype, что позволяет сети легко масштабироваться до очень больших размеров (в данный момент более 100 миллионов пользователей, 15—25 миллионов онлайн) без дорогой инфраструктуры централизованных серверов.

Кроме того, Skype может маршрутизировать звонки через компьютеры других пользователей. Это позволяет соединяться друг с другом пользователям, находящимся за NAT или брандмауэром, однако создаёт дополнительную нагрузку на компьютеры и каналы пользователей, подключённых к Интернету напрямую.

Единственным центральным элементом для Skype является сервер идентификации, на котором хранятся учётные записи пользователей и резервные копии их списков контактов. Центральный сервер нужен только для установки связи. После того как связь установлена, компьютеры пересылают голосовые данные напрямую друг другу (если между ними есть прямая связь) или через Skype-посредник (суперузел — компьютер, у которого есть внешний IP-адрес и открыт TCP-порт для Skype). В частности, если два компьютера, находящиеся внутри одной локальной сети, установили между собой Skype-соединение, то связь с Интернетом можно прервать и разговор будет продолжаться вплоть до его завершения пользователями или какого-либо сбоя связи внутри локальной сети.

Благодаря используемым Skype кодекам (алгоритмам сжатия данных) SILK (8-24 кГц), G.729 (8 кГц) и G.711 (ранее использовались также ILBC и ISAC) и при достаточной скорости интернет-соединения (30—60 кбит/с) в большинстве случаев качество звука сопоставимо с качеством обычной телефонной связи, а при хороших условиях соединения заметно лучше.

При установке соединения между ПК данные шифруются при помощи AES-256, для передачи ключа которого, в свою очередь, используется 1024-битный ключ RSA. Открытые ключи пользователей сертифицируются центральным сервером Skype при входе в систему с использованием 1536- или 2048-битных сертификатов RSA.^[38]

Протокол Skype (англ.) закрыт и используется только оригинальным программным обеспечением Skype. При помощи API к его функциям могут получать доступ программы сторонних разработчиков.

3 июня 2011 протокол Skype был взломан и его исходный код оказался в Интернете.^[39]

Официально подтверждённых разработчиком случаев расшифровки и/или перехвата данных в Skype не зафиксировано, и большинство спецслужб выражают по этому поводу недовольство.^[40][41] Однако правоохранительные органы Австрии на встрече с провайдерами в местном Министерстве внутренних дел сообщили, что провели «законный перехват IP-трафика» 25 июня 2008 года.^[42] Аналогичное заявление прозвучало и от представителя органов внутренних дел Австралии.^[43] Также, благодаря утечке информации^[44], стало известно о разработке фирмой Digitask программы перехвата онлайн-коммуникаций по заказу одного из министерств Баварии^[45], а компания FaceTime разработала сканер защищённых IM-сообщений Skype^[46]. Кроме того, о наличии решений для прослушивания Skype объявили власти Швейцарии^[47] и российские спецслужбы^[48].

Для стабильного использования видеосвязи необходима скорость интернет-соединения более 200 кбит/с и желательна тактовая частота процессора не менее 1 ГГц.

Чат

Skype позволяет пользователям общаться не только с помощью голоса, но и более традиционным способом — с помощью текстовых сообщений (IM-чата). Голосовой чат позволяет разговаривать как с одним пользователем, так и устраивать конференц-связь. Он использует собственные кодеки.

Skype-чат позволяет устраивать групповые чаты, посылать смайлики, хранить историю. Также предоставляются обычные для IM-чатов возможности — профили пользователя, индикаторы состояния (статус) и так далее. Кроме того, Skype предоставляет возможность обмена файлами без ограничения размера и со стандартными опциями временной остановки пересылки и автоматического возобновления при подключении после потери связи или выключения программы Skype до конца передачи файла.

Трафик

Размер трафика, потребляемого Skype при разговоре, может варьироваться, в зависимости от некоторых факторов, таких как скорость подключения к сети Интернет (и вызывающего и вызываемого), а также от насыщенности самого разговора.

Количество трафика, потребляемого Skype, особенно если дело касается передачи видео, напрямую зависит от ширины канала. Также Skype всегда подстраивается как под скорость соединения Интернет, так и под ресурсы системы. Таким образом, трафик при видеозвонке в разных условиях может очень сильно отличаться.

• При голосовом звонке и широкополосном подключении к Интернет расходуется примерно одинаковое количество входящего и исходящего трафика. В сумме средний объём трафика составляет около 500 кбайт/минуту (10 минут ~ 5 Мбайт; 100 минут ~ 50 Мбайт).

• При видеозвонке — примерно в 10 раз больше, чем при голосовом (и тем больше, чем шире канал и шумнее видео с веб-камеры), то есть ~5 Мбайт/мин, и никак не зависит от точки на Земле, с которой налажено соединение.

Если трафик при включенном Skype сильно завышен (даже в тех случаях когда нет чатов, бесед и видео отключено), то скорее всего клиент Skype стал «СуперНодом». В этом случае Skype начинает пропускать через себя «чужой» трафик по принципу работы пиринговой сети.^[49]

HTML

До версии 5.8.0.154 была возможность использовать HTML-теги (для выделения текста курсивом и полужирным начертанием, вставки ссылок, списков и т. п.) при отправке сообщений.^{[источник не указан 139 дней]} Для этого нужно было зажать  Ctrl  +  ⇧ Shift  и нажать на кнопку отправки сообщения. С версии 5.8.0.154 возможность отправки таких сообщений была отключена; тем не менее, при получении сообщения с тегами (например, отправленного из старой версии) они используются (за исключением версии для Linux).

Платформы

Существуют версии Skype для Linux, Mac OS X, iOS (iPhone, iPod touch и iPad), Windows (2000, XP, Vista, 7, 8, Windows Mobile, Windows Phone), PSP, Symbian OS, Java (мобильных телефонов), Android^[50].

В феврале 2010 года Skype прекратил разработку и поддержку клиентов для Windows Mobile и Skype Lite для Java. Соответствующие версии убраны с сайта Skype.^[51][52][53]

Услуги

Бесплатные услуги

• SkypeCast (от англ. Skype — программа VoIP и broadcasting — широковещание, иногда используется сокращённое «каст») — вид голосового общения между группой пользователей программы Skype (до 150 человек). Внешне схож с конференц-звонком, однако, в отличие от него, устанавливается через центральный сервер, вследствие чего не предъявляет высоких требований к пропускной способности канала пользователя, инициировавшего разговор. Услуга больше не предоставляется.

• Skype Voicemail — голосовая почта. Услуга запущена 10 марта 2005 года. Позволяет записывать входящие сообщения, когда пользователь не в сети, и работает как автоответчик.

• Skype Me. Связав пользователей по всему миру с помощью голоса, Skype дал возможность людям из разных стран общаться друг с другом. Для облегчения этой задачи Skype предлагает устанавливать статус SkypeMe, который указывает, что данный абонент открыт для звонков со всего мира. Установка данного статуса привлекает пользователей, желающих попрактиковаться в иностранном языке, а также мошенников и спамеров,^[54] поэтому начиная с 4 версии статус SkypeMe удален из программы.

Платные услуги

• SkypeOut — звонки на телефоны. Позволяет совершать исходящие звонки на стационарные и мобильные телефоны в большинстве стран мира. Оплата поминутная, дифференцированная. Звонки на бесплатные номера (такие, как +1 800 в США) бесплатны, причём воспользоваться ими могут даже пользователи, не оплачивавшие услугу SkypeOut.^[55][56] Также через SkypeOut производятся входящие Skype-звонки на телефон c мобильным приложением Skype Lite.^[57] Через 180 дней после последнего звонка SkypeOut баланс истекает.

• SkypeIn — онлайновый номер. Позволяет получать телефонные звонки от пользователей традиционных телефонных сетей. При этом участник получает телефонный номер в одной из следующих стран: Австралия, Бразилия, Германия, Дания, Польша, Швеция, Швейцария, Финляндия, Эстония, Франция, Великобритания, США, Япония и Гонконг (Китай). Все входящие звонки на данный номер будут приходить на учётную запись Skype, а при положительном счёте возможна переадресация звонков на любой телефонный номер. В качестве бонуса к телефонному номеру компания Skype бесплатно предоставляет автоответчик на всё время использования номера. Российские онлайновые номера для Skype предоставляют некоторые операторы IP-телефонии.

• Номер Skype To Go — специальный номер доступа, на который можно позвонить с любого телефона (стационарного или мобильного) для того, чтобы связаться с другим номером по установленным тарифам, денежные средства при этом снимаются со счета Skype.

• Отправка SMS — возможность отправлять SMS сообщения из программы Skype на мобильные телефоны.

Услуги для бизнеса

Для корпоративного сегмента рынка Skype предлагает услугу Skype для SIP Open Beta.^[58] и её более функциональную разновидность Skype Connect^[59] Необходимое количество линий оплачивается ежемесячно.

Данные услуги позволяют компаниям обеспечить прямой доступ из своей корпоративной сети связи прямо в сеть Skype, а именно: принимать на офисные телефоны звонки из сети Skype и совершать с офисных телефонов звонки в сеть Skype. Доступ к сети Skype реализуется с помощью VoIP-шлюзов (через офисные аналоговые или цифровые АТС) или через IP-АТС компании. Совместимое со Skype оборудование сегодня выпускается такими вендорами как Avaya, Cisco, AddPac.

Гаджеты и товары

Skype выпускает и продает различные товары для программы Skype. Например, беспроводной телефон RTX Dualphone 3088 для звонков без компьютера.^[60] Телефон позволяет звонить и принимать звонки как через Skype, так и в обычной телефонной сети без компьютера. Также, Skype выпускает гарнитуры Freetalk Wireless — беспроводные наушники с USB-передатчиком для беспроводного общения по Skype^[61], аппаратуру для видеозвонков (Freetalk Buddy Pack)^[62] и веб-камеры (Freetalk Connect 2)^[63].

Проблемы

Сбои

16 августа 2007 года сервис Skype был недоступен по всему миру.^[64]

22 и 23 декабря 2010 года сервис Skype был недоступен огромному количеству пользователей.^[65][66]

26—27 мая 2011 года — сбой Skype у отдельных пользователей по всему миру.^[67]

3 июня 2011 года произошёл первый случай взлома протокола Skype с утечкой исходного кода в Интернет.^[68]

7 июня 2011 года — сбой Skype по всему миру.^[69]

Skype и операторы сотовой связи

Клиент Skype можно установить на совместимый телефон^[57] или КПК^[70][71][72], при этом получается значительная экономия средств по причине невысоких тарифов системы. Однако сотовые операторы не хотят терять доход и всячески тормозят процесс.^[73][74] T-Mobile — крупнейший провайдер сотовой связи в Германии — заявил, что будет блокировать трафик интернет-телефонии Skype на смартфонах iPhone.^[74][75] Аналогичным образом поступила одна из крупнейших в США телекоммуникационных компаний AT&T, которой в дальнейшем под давлением FCC пришлось все-таки разрешить Skype в сетях 3G и EDGE.^[76] Дело доходит до того, что лобби сотовых операторов пытается запретить Skype, а заодно и ICQ, на территории России.^[77] Однако в сети оператора «Скай Линк» передача данных по протоколу Skype не тарифицируется — в январе 2010 года компания ввела опцию «Безлимитный Skype»^[78] для абонентов Московского региона.

Противодействие со стороны «МегаФон»

В России активную борьбу против Skype ведет компания «МегаФон», которая старается ограничить доступ к сервисам Skype в своих сетях^[79] и даже взимает плату за его использование^[80]. Также, «Мегафон» пытался ограничить доступ к Skype и на законодательном уровне.^[81]

Многие пользователи компании «МегаФон», использующие Skype для отправки СМС на «МегаФон», жалуются на то, что эти сообщения не доходят. Специалисты Skype заявляют, что в этом виновата компания «МегаФон»^{[источник не указан 488 дней]}.

Попытки запрета Skype

Россия

В России периодически возникают предложения запретить Skype; при этом аргументацией выступает угроза безопасности, связанная с шифрованием разговоров и отсутствием подключения к СОРМ.^[82][83]

Белоруссия

В Белоруссии услуги стационарной телефонной связи должны проходить через государственного оператора, а оказание услуг международной связи с использованием других сетей, включая Skype, без наличия специального разрешения (лицензии) Министерства связи и информатизации Республики Беларусь является нарушением законодательства.^[84] При этом законодательством не запрещено использование услуг телефонии по IP-протоколу (в том числе с помощью программного обеспечения Skype) для личного пользования.^[85]

Германия

Крупнейшая европейская телекоммуникационная компания Deutsche Telekom заявила, что будет блокировать Skype при попытке использования её с iPhone.^[86]

Китай

В январе 2011 года власти Китая выпустили постановление, которое запрещает жителям страны пользоваться услугами всех поставщиков услуг интернет-телефонии, включая популярный сервис Skype, кроме официальных провайдеров China Telecom.^[87][88][89]

Объединённые Арабские Эмираты

Доступ к Skype может быть заблокирован аппаратными средствами. Подобные решения есть у Verso Technologies и Cisco Systems. В частности, ими пользуется крупнейший китайский провайдер China Telecom.^[90] До марта 2010 года аналогичным образом Skype блокировали в ОАЭ.^[91][92]

Ответные действия со стороны Skype

В ответ на попытки запрета Skype его разработчики начали внедрять в программу средства маскировки трафика для обхода блокировки VoIP.^[93] Кроме того, Skype может работать внутри анонимной сети I2P, подвергаясь при этом дополнительному многоуровневому шифрованию и анонимизации, также Skype может работать с прокси-серверами, VPN и Tor^[94], что практически сводит на нет эффективность его блокировки.

Критика

• При некоторых обстоятельствах (широкий канал, глобальный IP адрес, постоянное включение и т. п.) компьютер клиента может использоваться как сервер сети (режим supernode), что приводит к существенной загрузке компьютера и большому трафику. Пользователь при этом не получает уведомлений и не имеет штатных средств в программе для запрета такого действия. В версии для платформы Windows эту функцию можно отключить редактированием реестра.

• Skype практически невозможно прослушать, за что его критикуют спецслужбы многих стран.^[95] В то же время сам сервис не раз обвинялся в шпионаже в пользу США и Китая.^[96]

• Одним из недостатков Skype считается использование проприетарного протокола, несовместимого с открытыми стандартами (такими, как SIP или H.323).

• На конференции Black Hat Europe 2006, посвящённой вопросам информационной безопасности, был представлен анализ Skype.^[97] Среди прочего, там были отмечены:

• интенсивное использование антиотладочных приёмов и обфусцированного кода;
• постоянная передача данных (даже в ситуациях, когда сама программа находится в режиме ожидания);
• использование 3G-сетей.

• Крис Касперски активно критикует Skype^[98]:

Skype — это чёрный ящик с многоуровневой системой шифрования, напичканной антиотладочными приёмами исполняемого файла, считывающий с компьютера конфиденциальную информацию и передающий её в сеть по закрытому протоколу. Последний обходит брандмауэры и сурово маскирует свой трафик, препятствуя его блокированию. Всё это превращает Skype в идеального переносчика вирусов, червей и дронов, создающих свои собственные распределённые сети внутри Skype-сети. …

Skype активно изучается в хакерских лабораториях и security-организациях по всему миру, и большинство исследователей единодушно сходятся во мнении, что Skype — это дьявольски хитрая программа, написанная бесспорно талантливыми людьми в стиле Black Magic Art. Skype не брезгует грязными трюками, создающими огромные проблемы.

• В феврале 2007 стало известно об ошибке, в результате которой Skype создаёт в каталоге для временных файлов файл 1.com, который позволяет считывать информацию из BIOS. Согласно информации из официального блога, это было вызвано использовавшейся в подключаемом модуле Skype Extras Manager системы безопасности, изготовленной фирмой EasyBits Software, которая таким образом получала серийный номер материнской платы для однозначной идентификации компьютера.^[99] Данная система не используется в версиях 3.0.0.216 и старше.

• Как и любая сеть, работающая по принципу P2P, Skype подвержен вирусным эпидемиям. Уже известны случаи распространения вредоносных программ, перехватывающих и записывающих разговоры в Skype.^[100]

• 24 мая 2011 года при попытке зайти в бизнес-аккаунт с помощью браузера Mozilla Firefox выдавалось предупреждение о том, что «manager.skype.com использует недействительный сертификат безопасности».^[101]

• 14 ноября 2012 года в сервисе голосовой и видеосвязи Skype обнаружили критическую уязвимость, которая позволяет взломать любой аккаунт, зная лишь почту, на которую зарегистрирован этот аккаунт. ^[102]

Пасхальные яйца

• При последовательном зажатии 3 и более кнопок на клавиатуре, при набирании текста в окошке, собеседник увидит не пишущий карандаш, а кошку.
• При нажатии кнопок в хаотическом порядке можно увидеть руки, которые разламывают карандаш на две части.
• Помимо встроенных смайликов, Skype содержит несколько «секретных» (в зависимости от версии они могут присутствовать в стандартных смайликах). Вот они^[103]:

• (bandit) — бандит
• (bug) — жук
• (call) — звонить
• (drunk) — пьяный смайл
• (e) — письмо/email
• (film) или (~) — фильм
• (finger) — показывает cредний палец
• (flag: «2 буквы государства»), например флаг России — (flag:RU), флаг США — (flag:US)
• (football) — футбол (работает начиная со Skype 5.9)
• (fubar) — тычет пальцем
• (headbang) — бьётся головой об стену
• (highfive), (hifive) или (h5) — «дай пять»
• (hollest) — женские ножки
• (lalala), (lala) или (notlistening) — «ля-ля-ля, я тебя не слушаю»
• (mooning) — демонстрация ягодиц
• (mp) — телефон
• (o) — часы
• (oliver) — некто Оливер (работает начиная со Skype 5.8)
• (poolparty) — вечеринка в бассейне
• (punch) — удар
• (rock) — рок
• (smoking) или (ci) — курящий смайл
• (ss) — значок скайпа
• (swear) — ругается матом
• (talk) — говорить
• (tmi) — слишком много информации
• (toivo) — мальчик с собакой
• (u) — разбитое сердце
• (wfh) — работаю из дома
• (wtf) — что происходит?
• (zilmer) — фотограф

• Если в настройках программы изменить шрифт окна сообщений на Comic Sans, то смайлик на кнопке смайликов внизу окна сменится на грустный (версия 5.5 для Windows)

См. также

• Безопасность в Skype
• Сравнение программ для IP-телефонии
• Google Talk
• Forfone
• Jingle (протокол)
• WebRTC (протокол)
• FaceTime

Примечания

Литература

• Яковлева Е. С. Самоучитель Skype. Бесплатная связь через Интернет. — СПб.: БХВ-Петербург, 2008. — С. 304. — ISBN 978-5-9775-0177-4

Ссылки

Сайты и ресурсы

• Официальный сайт (рус.)
• SkypeClub (рус.)

Статьи

• Безопасность Skype в корпоративной среде (рус.)
• Skype для каждого — интересные возможности и дополнения (рус.)

Обзоры

• Обзор приложений для Linux. Часть III: коммуникационные программы. Tom’s Hardware Guide Russia (16 ноября 2009). Архивировано из первоисточника 25 августа 2011. Проверено 8 января 2010.
• Андрей Пировских. Skype против Gizmo: бесплатная интернет-телефония. Tom’s Hardware Guide Russia (10 марта 2006). Архивировано из первоисточника 25 августа 2011. Проверено 23 июля 2010.

Программное обеспечение для служб мгновенного обмена сообщениями (сравнение)
Протоколы	Gadu-Gadu • OSCAR (ICQ) • QQ • XMPP (Jabber)
Серверы	Ejabberd • IceWarp • iChat Server • Openfire • Prosody
Клиенты
Мульти- протокольные	Adium • CenterIM • Digsby • Empathy • fring • iChat • IMadering • IM+ • Instantbird • Kopete • Licq • mChat • Miranda IM • Pidgin • QIP Infium • QIP PDA Symbian • Qnext • qutIM • SIM • Talkonaut • Trillian • Virtus
OSCAR (ICQ)	&RQ • ICQ • Jimm • QIP 2005 • R&Q
XMPP (Jabber)	Bombus • Bombusmod • Exodus • Gajim • Gizmo5 • Google Talk • Gossip • Jabbim • Jabbin • JWChat • Psi • SamePlace • Spark • Tkabber • Я.Онлайн
.NET Messenger	aMSN • emesene • KMess • Microsoft Messenger for Mac • Windows Live Messenger
Прочие	AIM • Boljoo • Camfrog • Comodo Unite • Ekiga • Gadu-Gadu • Jitsi • Linphone • Mail.Ru Агент • Messenger Plus! Live • meebo • imo.im • MySpaceIM • naim • ooVoo • Skype • QQ • Twinkle • Xfire • Yahoo! Messenger

Схемы URI
Официальные	aaa: • aaas: • acap: • cap: • cid: • crid: • data: • dav: • dict: • dns: • fax: • file: • ftp: • go: • gopher: • h323: • http: • https: • im: • imap: • ldap: • mailto: • mid: • news: • nfs: • nntp: • pop: • pres: • rtsp: • sip: • sips: • snmp: • tel: • telnet: • urn: • wais: • xmpp:
Неофициальные	about: • aim: • bolo: • btc: • bzr: • callto: • chrome: • cvs: • daap: • ed2k: • ed2kftp: • feed: • fish: • git: • gizmoproject: • iax2: • irc: • ircs: • lastfm: • ldaps: • magnet: • mms: • msnim: • psyc: • rsync: • secondlife: • skype: • ssh: • svn: • sftp: • smb: • sms: • soldat: • steam: • unreal: • ut2004: • view-source: • vzochat: • webcal: • xfire: • ymsgr:

Основные протоколы TCP/IP по уровням модели OSI (Список портов TCP и UDP)
Физический	Ethernet • RS-232 • EIA-422 • RS-449 • RS-485
Канальный	Ethernet • PPPoE • PPP • L2F • 802.11 Wi-Fi • 802.16 WiMax • Token ring • ARCNET • FDDI • HDLC • SLIP • ATM • CAN • DTM • X.25 • Frame relay • SMDS • STP • ERPS
Сетевой	IPv4 • IPv6 • IPsec • ICMP • IGMP • ARP • RARP • RIP2 • OSPF
Транспортный	TCP • UDP • SCTP • DCCP • RDP/RUDP • RTP • GRE
Сеансовый	ADSP • H.245 • iSNS • NetBIOS • PAP • RPC • L2TP • PPTP • RTCP • SMPP • SCP • ZIP • SDP
Представления	XDR • SSL • TLS
Прикладной	BGP • HTTP • HTTPS • DHCP • IRC • SNMP • DNS • DNSSEC • NNTP • XMPP • SIP • IPP • NTP • SNTP • Электронная почта (SMTP • POP3 • IMAP4) • Передача файлов (FTP • TFTP • SFTP) • Удалённый доступ (rlogin • Telnet • SSH • RDP)
Другие прикладные	OSCAR • CDDB • Multicast FTP • Multisource FTP • BitTorrent • Gnutella • Skype