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{{Infolentelė programinė įranga
| pavadinimas = Telegram
| logotipas = Telegram logo.svg
| logotipo dydis = 100px
| logotipo antraštė =
| ekrano nuotrauka = Telegram Android screenshot (v 3.3, English).png
| antraštė = „Telegram“ Android 6.0 Lollipop sistemoje, versija 3.3
| autorius =
| kūrėjas = Telegram Messenger LLP
| išleista = 2013 m. birželio 30 d.
| paskutinė versija = [[Android]] - 4.3.1, [[iOS]] - 4.3, [[Windows Phone]] - 2.6, kompiuterinė versija - 1.1.23, [[macOS]] programėlė - 3.2
| būsena =
| programavimo kalba =
| operacinė sistema =
| platforma = [[Android]], [[iOS]], [[Windows]], [[Windows Phone]] (Windows 10 Mobile), [[macOS]], [[Linux]], naršyklės svetainė
| dydis = priklauso nuo įrenginio
| kalba = anglų, ispanų, vokiečių, olandų, italų, arabų, portugalų, korėjiečių + įvairūs vartotojų paketai, skirti kitoms kalboms
| žanras = [[muzika|muzikos]] ir vaizdo įrašų transliavimo internetu platforma
| licencija = GNU GPLv2 ar GPLv3
| svetainė = {{URL|http://telegram.org}}
}}
'''Telegram''' yra nemokama, pelno nesiekianti<ref>[https://telegram.org/faq#q-how-are-you-going-to-make-money-out-of-this Telegram F.A.Q], "...making profits will never be an end-goal for Telegram."</ref><ref>[https://www.theverge.com/2014/2/25/5445864/telegram-messenger-hottest-app-in-the-world Why Telegram has become the hottest messaging app in the world], The Verge. Retrieved 25 February 2014. "Telegram operates as a non-profit organization, and doesn’t plan to charge for its services."</ref>, atvirojo kodo [[programėlė]], skirta susirašinėjimams ir pokalbiams, veikianti debesų technologijos pagrindu. Telegram klientai veikia beveik visose svarbiausiose platformose, įskaitant [[Android]], [[iOS]], [[Windows Phone]], [[Windows NT]], [[macOS]] ir [[Linux]].<ref name="teleapps">{{cite web|url=https://telegram.org/apps|title=List of Telegram applications|date=6 February 2014}}</ref> Vartotojai gali siųsti pranešimus ir keistis nuotraukomis, vaizdo ir garso įrašais, lipdukais, įvairių tipų failais. Taip pat yra pasirenkamas šifruojamasis bendravimas, t.y. nuo galo-iki galo bendravimas, kuomet serveryje nėra jokių duomenų apie tokį bendravimą ir viskas yra šifruojama.
Telegram pagrindinis rėmėjas yra Pavel Durov<ref name="TelegramFAQ">{{cite web|url = https://telegram.org/faq#q-who-are-the-people-behind-telegram|title = Telegram FAQ|date = 9 August 2015}}</ref>. Šios programėlės kodas yra atvirojo tipo, nors taip pat naudoja dalį uždaro kodo, bet pirminis kodas ne visada yra iškart paskelbiamas<ref name="GitHub">{{cite web|url=https://github.com/DrKLO/Telegram/commits/master|title=Latest commits from official repository (Android version)|last=|first=|date=10 April 2016|website=Github|archive-url=|archive-date=|dead-url=|access-date=}}</ref>, kadangi programėlės serverio pusės kodas yra uždaro tipo ir patentuotas. Paslauga taip pat teikia API kodą nepriklausomiems kūrėjams. 2016 metų vasario mėn., Telegram pranešė, kad kasdien 100 milijonų aktyvių vartotojų persiunčia vidutiniškai 15 milijardų žinučių per dieną.
Apsauga buvo daug kartų tikrinta. Šios programėlės veikimo principo kritikai tikina, kad Telegram apsaugos modelis yra pažeistas dėl savo, kitokio tipo protokolo, kuris niekada nebuvo įrodytas būnant patikimu ir saugiu bei dėl slapto bendravimo neįgalinimo iškart. Telegram taip pat sulaukė kritikos dėl plataus teroristinės ISIS organizacijos vartojimo.
Pasak Telegram savininko, 2017 metų balandį Telegram turėjo virš 40 milijonų aktyvių vartotojų [[Iranas|Irane]], tokiu būdu pralenkiant visas kitas panašaus pobūdžio programėles.<ref>{{Cite web|url=https://cpj.org/blog/2017/05/iran-targets-telegram-app-as-it-seeks-to-control-n.php|title=Iran targets Telegram app as it seeks to control news ahead of May election - Committee to Protect Journalists|website=cpj.org|language=en|access-date=2017-05-18}}</ref>
== Istorija ==
=== Vystymasis ===
Pirmą kartą Telegram buvo paleista 2013 metais brolių Nikolaj ir Pavel Durovų, kurie prieš tai buvo sukūrę socialinį tinklą [[vK]] [[Rusija|Rusijoje]]. Nikolaj Durov sukūrė specialų MTProto protokolą, kurio remiasi ši paslauga.
Telegram yra registruota kaip angliška LLP<ref>{{Cite web|title = Telegram - Android Apps on Google Play|url = https://play.google.com/store/apps/details?id=org.telegram.messenger|website = play.google.com|accessdate = 19 November 2015}}</ref> bei amerikietiškojo LLC<ref>{{Cite web|title = Telegram Messenger on the App Store|url = https://itunes.apple.com/app/telegram-messenger/id686449807|website = App Store|accessdate = 19 November 2015}}</ref> tipo bendrovė. Paslaugos teikėjai teigia, jog būstinė įsikūrusi [[Berlynas|Berlyne]], [[Vokietija|Vokietijoje]]<ref name="TheVergeKorea">{{cite web|url = https://www.theverge.com/2014/10/6/6926205/surveillance-drives-south-koreans-to-encrypted-messaging-apps|title = Surveillance drives South Koreans to encrypted messaging apps|date = 6 October 2014|website = [[The Verge]]|accessdate = 19 November 2015|first = Russell|last = Brandom}}</ref>, Ši bendrovė įprastai neturi savo faktinės pastovios būstinės, nes programuotojų komanda nori išvengti įvairių vyriausybių įtakos programėlės vystyme. Pavel Durov paliko Rusiją ir pareiškė, jog jis keis savo gyvenamąją šalį su savo maža programuotojų grupele<ref name=":0">{{Cite news|title = Once Celebrated in Russia, the Programmer Pavel Durov Chooses Exile|url = https://www.nytimes.com/2014/12/03/technology/once-celebrated-in-russia-programmer-pavel-durov-chooses-exile.html|newspaper = [[The New York Times]]|date = 2 December 2014|access-date = 19 November 2015|first = Danny|last = Hakim}}</ref>.
=== Vartojimo apimtys ===
2013 metų spalio mėn., Telegram turėjo 100 000 aktyvių vartotojų<ref name="TechCrunch" /> On 24 March 2014, Telegram announced that it had reached 35 million monthly users and 15 million daily active users.<ref>{{Citation|url=https://techcrunch.com/2014/03/24/telegram-hits-35m-monthly-users-15m-daily-with-8b-messages-received-over-30-days/|publisher=TechCrunch|title=Telegram Hits 35M Monthly Users, 15M Daily With 8B Messages Received Over 30 Days|date=24 March 2014}}</ref>. Tą patį 2014 metų mėnesį, [[Pietų Korėja|Pietų Korėjos]] vyriausybė pradėjo skatinti savo piliečius pradėti vartoti būtent šią programėlę. 2014 metų gruodį, Telegram turėjo 50 milijonų aktyvių vartotojų, kurie siuntinėdavo virš milijardo žinučių per dieną, bei po 1 milijoną naujų vartotojų, užsiregistruojančių kiekvieną savaitę<ref>{{Citation|url=https://telegram.org/blog/billion|publisher=Telegram|title=Telegram Reaches 1 Billion Daily Messages|date=8 December 2014}}</ref>; vartojimo apimtys dvigubinosi per penkius mėnesius su 2 milijardais kasdienių žinučių<ref>{{Citation|url=https://telegram.org/blog/2-billion|publisher=Telegram|title=Telegram Hits 2 Billion Messages Sent Daily|date=13 May 2015}}</ref>. 2015 metų rugsėjį, oficialioj svetainėj buvo pranešta, jog pasiektas 60 milijonų aktyvių vartotojų skaičius, su 12 milijardų žinučių kasdien<ref>{{Cite web|url = https://techcrunch.com/2015/09/21/telegram-now-seeing-12bn-daily-messages-up-from-1m-in-february/|title = Telegram Now Seeing 12BN Daily Messages, up From 1BN in February|date = 21 September 2015|accessdate = 19 November 2015|website = [[Techcrunch]]|last = Lomas|first = Natasha}}</ref>. 2016 metų vasarį, Telegram pranešė pasiekę 100 milijonų aktyvių vartotojų per mėnesį, su 350 tūkst. naujų vartotojų kasdien bei 15 milijardų žinučių kasdien<ref>{{Cite web|title = Encrypted Messaging App Telegram Hits 100M Monthly Active Users, 350k New Users Each Day|url = https://techcrunch.com/2016/02/23/encrypted-messaging-app-telegram-hits-100m-monthly-active-users-350k-new-users-each-day/|website = TechCrunch|access-date = 23 February 2016|first = Matt|last = Burns|date = 23 February 2016}}</ref>.
== Galimybės ==
=== Paskyra ===
Telegram paskyros yra tiseiogiai susietos su telefono numeriais, taip suteikiant galimybę patvirtinti tam tikrus veiksmus [[SMS]] žinute ar telefono skambučiu<ref name="Lopez">{{Citation|url=http://www.applesfera.com/aplicaciones-ios-1/configurando-telegram-en-el-iphone-en-la-web-y-en-el-mac|title=Configurando Telegram en el iPhone, en la web y en el Mac|first=Miguel|last=Lopez|trans_title=Configuring Telegram in the Apple iPhone, the Web and the Mac|language=es|publisher=Applesfera|accessdate=4 December 2014}}</ref>. Vartotojai gali naudotis paslauga daugeliu prietaisų vienu metu bei gauti pranešimus tiesiai į visus juos. Prijungti įrenginiai gali būti atjungti po vieną ar visi iškart. Susietasis numeris gali būti bet kada pakeistas, ir visi kontaktai iškart gauną naują numerį, jeigu turi senąjį.<ref name="Lopez" /><ref name="way-transf">{{cite web|url = http://www.wayerless.com/2014/12/telegram-se-actualiza-permitiendo-ahora-migrar-tus-conversaciones-y-contactos-a-una-linea-nueva/|first = Jonathan|last = Munizaga|date = 1 December 2014|trans_title = Telegram already allows migrating conversations and contacts to a new line|title = Telegram ya permite migrar conversaciones y contactos a una línea nueva|publisher = Wayerless|accessdate = 2 December 2014|language = es}}</ref><ref name="te-transf">{{cite web|language = es|url = http://www.tuexpertoapps.com/2014/12/02/telegram-ahora-permite-traspasar-mensajes-al-cambiar-de-numero/|first = David G|last = Mateo|date = 1 December 2014|title = Telegram ahora permite traspasar mensajes al cambiar de número|publisher = TuExperto|accessdate = 2 December 2014}}</ref>. Papildomai, vartotojai gali susigalvoję sau priskirti vartotojo vardą arba pseudonimą, kurio gali rašyti visi kiti vartotojai, taip neatskleidžiant senojo numerio.<ref name="cs2.0">{{cite web|url=https://techcrunch.com/2014/10/23/secure-messaging-app-telegram-adds-usernames-and-snapchat-like-hold-to-view-for-media/|title=Secure Messaging App Telegram Adds Usernames And Snapchat-Like Hold-To-View For Media|publisher=Techcrunch|date=23 October 2014|accessdate=23 October 2014}}</ref>. Telegram paskyros gali būti ištrintos bet kada arba po šešių mėnesio neaktyvumo laikotarpio, kuris gali būti pasirinktinai pratęstas tarp 1 mėnesio ir 1 metų. Vartotojai gali nustatyti „paskutinį kartą matytas/-a prieš ...“ ("last seen") pranešimo matomumą bei tipą, kad įvairūs vartotojai matytų vis kitokį pranešimą ir vis kitaip. <ref>{{cite web|title=Hiding Last Seen Time - Done Right|url=https://telegram.org/blog/privacy-revolution|accessdate=18 May 2017}}</ref>.
Įprastinis metodas, skirtas prisijungti prie paskyros, yra SMS žinutė ar telefono skambutis. Kai kuriose šalyse, kur ši veikla sekama, pvz. Irane, Rusijoje, vartotojams siūloma įgalinti dviejų žingsnių tipo patvirtinimą, t.y. kai vartotojas neprivalo naudoti telefono žinute gauto kodo, bet gali naudoti slaptažodį. Tai nėra privaloma.
=== Pranešimai per debesį ===
Telegram pranešimai yra siunčiami per debesį, taip iškart pasiekiant visus vartotojo įrenginius. Vartotojai gali keistis nuotraukomis, vaizdo bei garso įrašais, kitais failais, siekiančiais iki 1,5 GB.<ref name="teleapps" /><ref name="20m">{{Cite web|url=http://www.20minutos.es/noticia/2069997/0/telegram/alternativa-whatsapp/gratis/|language=es|trans_title=Telegram: a free Whatsapp alternative with advantages and some obscure points|title=Telegram: una alternativa gratuita a WhatsApp con ventajas y algún punto oscuro|date=1 March 2014|accessdate=4 December 2014}}</ref>. Vartotojai gali siųsti žinutes privačiai bei grupėms iki 10 tūkst. vartotojų. <ref name="Venture-5k">{{cite news|url=https://telegram.org/blog/admin-revolution|title=Supergroups 10,000: Admin Tools & More|last1=|first1=|date=30 June 2017|work=Telegram|accessdate=|archive-url=|archive-date=|dead-url=}}</ref>. Išsiųsti pranešimai gali būti redaguoti bei ištrinti per 48 valandas nuo išsiuntimo. Tai suteikia galimybę ištaisyti klaidas ir pašalinti žinutes, išsiųstas per klaidą<ref name="Telegram Unsend Messages">{{Citation|url=https://telegram.org/blog/unsend-and-usage|publisher=Telegram|title=Unsend Messages, Network Usage, and More|date=3 January 2017|accessdate=4 April 2017}}</ref>. Pranešimai yra užšifruojami bei siunčiami per savą MTProto protokolą, per kurį duomenys yra stipriai užšifruojami, o šifrai laikomi daugelyje įvairių serverių. Tai suteikai galimybę apsaugoti privačią informaciją nuo įsilaužėlių bei svetimų asmenų<ref>{{Cite web|title = Telegram Privacy Policy|url = https://telegram.org/privacy|website = Telegram|access-date = 17 January 2016}}</ref>. Pranešimai bei kiti duomenys lieka serveriuose iki kol yra ištrinami.
==== Robotai ====
2015 metų birželį Telegram paleido platformą trečiųjų šalių kūrėjams, suteikiant sukurti specialius pokalbių robotus. In June 2015, Telegram launched a platform for third-party developers to create [[IM bot|bots]].<ref name="Telegram Bot Platform">{{Citation|url=https://telegram.org/blog/bot-revolution|publisher=Telegram|title=Telegram Bot Platform|date=24 June 2015|accessdate=1 September 2015}}</ref> Bots are Telegram accounts operated by programs. They can respond to messages or [[Mention (blogging)|mentions]], can be invited into groups and can be integrated into other programs. Dutch website ''[[Tweakers]]'' reported that an invited bot can potentially read all group messages when the bot controller changes the access settings silently at a later point in time. Telegram pointed out that it considered implementing a feature that would announce such a status change within the relevant group.<ref>{{Cite web|url = http://tweakers.net/nieuws/104386/telegram-bots-kunnen-relatief-ongemerkt-meelezen-in-groepsgesprekken.html|title = Telegram-bots kunnen relatief ongemerkt meelezen in groepsgesprekken|date = 23 July 2015|accessdate = 25 October 2015|website = [[Tweakers]]|last = Schellevis|first = Joost|language = nl}}</ref> Also there are inline bots, which can be used from any chat screen. In order to activate an inline bot, user needs to type in the message field a bot's username and query. The bot then will offer its content. User can choose from that content and send it within a chat.<ref name="Inline Bots">{{Citation|url=https://telegram.org/blog/inline-bots|publisher=Telegram|title=Introducing Inline Bots|date=4 January 2016|accessdate=4 April 2017}}</ref>
==== Channels ====
Channels can be created for broadcasting messages to an unlimited number of subscribers.<ref>{{cite news|last1=Lobao|first1=Martim|title=Telegram v3.2 Brings Channels For Broadcasting Your Messages To The World|url=http://www.androidpolice.com/2015/09/22/telegram-v3-2-brings-channels-broadcasting-messages-world/|work=Android Police|date=22 September 2015}}</ref> Channels can be publicly available with an alias and a permanent URL so anyone can join. Users who join a channel can see the entire message history. Each message has its own view counter, showing how many users have seen this message. Users can join and leave channels at any time. Furthermore, users can mute a channel, meaning that the user will still receive messages, but won't be notified.
=== Stickers ===
Stickers are cloud-based, high-definition images intended to provide more expressive [[emoji]]. When typing in an emoji, the user is offered to send the respective sticker instead. Stickers come in collections called "sets", and multiple stickers can be offered for one emoji. Telegram comes with one default sticker set,<ref name="Telegram Stickers">{{Citation|url=https://telegram.org/blog/stickers-meet-art-and-history|publisher=Telegram|title=Telegram Stickers|date=2 January 2015|accessdate=5 January 2016}}</ref> but users can install additional sticker sets provided by third-party contributors. Sticker sets installed from one client become automatically available to all other clients. Sticker images use [[WebP]] file format, which is better optimized to be transmitted over internet.
=== Drafts ===
Drafts are unfinished messages synced across user devices. One can start typing a message on one device and continue on another. The draft will persist in editing area on any device until it is sent or removed.<ref name="Drafts">{{Citation|url=https://telegram.org/blog/drafts|publisher=Telegram|title=Drafts, Picture-in-Picture, and More|date=14 June 2016|accessdate=4 April 2017}}</ref>
=== Secret chats ===
[[File:Telegram secret chat - en.png|thumb|200px|A "secret chat" confirmation notice - screenshot from [[Android Marshmallow]].]]
Messages can also be sent with client-to-client encryption in so-called secret chats. These messages are encrypted with the service's MTProto protocol.<ref name="techfaq" /> Unlike Telegram's cloud-based messages, messages sent within a secret chat can be accessed only on the device upon which the secret chat was initiated and the device upon which the secret chat was accepted; they cannot be accessed on other devices.<ref name="TechCrunch" /><ref name="how-secure">{{Citation|url=https://telegram.org/faq#q-how-secure-is-telegram|publisher=Telegram|work=FAQ|title=How secure is Telegram?}}</ref><ref>{{Citation|publisher=Telegram|url=https://core.telegram.org/mtproto|title=Description of MTProto Mobile Protocol}}</ref> Messages sent within secret chats can, in principle, be deleted at any time and can optionally self-destruct.<ref>{{harvnb|Rottermanner|Kieseberg|Huber|Schmiedecker|2015|p=2}}</ref>
Secret chats have to be initiated and accepted by an invitation, upon which the encryption keys for the session are exchanged. Users in a secret chat can verify that no [[man-in-the-middle attack]] has occurred by comparing pictures that visualize their [[public key fingerprint]]s.<ref>{{cite web|last1=Hamburger|first1=Ellis|title=Why Telegram has become the hottest messaging app in the world|url=https://www.theverge.com/2014/2/25/5445864/telegram-messenger-hottest-app-in-the-world|website=The Verge|publisher=Vox Media|accessdate=17 March 2016|date=25 February 2014}}</ref>
According to Telegram, secret chats have supported [[perfect forward secrecy]] since December 2014. Encryption keys are periodically changed after a key has been used more than 100 times or has been in use for more than a week.<ref name="Rottermanner-2015-p6">{{harvnb|Rottermanner|Kieseberg|Huber|Schmiedecker|2015|p=6}}</ref> Old encryption keys are destroyed.<ref name="way-transf" /><ref name="te-transf" /><ref>{{Citation|url=https://core.telegram.org/api/end-to-end/pfs|publisher=Telegram|title=Perfect Forward Secrecy|date=14 December 2014}}</ref>
Windows and Linux users are still not able to use secret chats using the official Telegram Desktop app while the official macOS-only client supports them. <ref>{{cite web|title = Github issue 871: missing secret chats|url = https://github.com/telegramdesktop/tdesktop/issues/871|date = 2 July 2015|accessdate = 25 July 2017}}</ref>
Secret chats are not available for groups or channels.
Telegram's local message database is not encrypted by default.<ref name="Rottermanner-2015-p6"/> Some Telegram clients allow users to encrypt the local message database by setting a passphrase.<ref name="zimperium">{{cite news|last1=Franceschi-Bicchierai|first1=Lorenzo|title=Encryption Fails: When to Freak Out and When to Chill|url=http://motherboard.vice.com/read/encryption-fails-when-to-freak-out-and-when-to-chill|work=Motherboard|publisher=Vice Media|date=24 February 2015|accessdate=9 January 2016}}</ref>
=== Voice calls ===
In the end of March 2017, Telegram introduced its own [[Voice call|voice calls]]. The calls are built upon the end-to-end encryption of Secret Chats. Connection is established as [[peer-to-peer]] whenever possible, otherwise the closest server to the client is used. According to Telegram, there is a [[Artificial neural network|neural network]] working to learn various technical parameters about call to provide better quality of the service for future uses. After a brief initial trial in Western Europe, voice calls are now available for use in most countries.<ref name="Telegram Voice Calls">{{Citation|url=https://telegram.org/blog/calls|publisher=Telegram|title=Voice Calls: Secure, Crystal-Clear, AI-Powered|date=30 March 2017|accessdate=3 April 2017}}</ref>
== Architecture ==
=== Encryption scheme ===
[[File:Explanation of secret chats (Telegram).png|thumb|200px|A simplified illustration of the MTProto encryption scheme.]]
Telegram uses a [[symmetric encryption]] scheme called MTProto. The protocol was developed by Nikolai Durov and other developers at Telegram and is based on 256-bit symmetric [[Advanced Encryption Standard|AES]] encryption, [[RSA (cryptosystem)|RSA]] 2048 encryption and [[Diffie–Hellman key exchange]].<ref name="techfaq">{{cite web|url = https://core.telegram.org/techfaq|title = FAQ for the Technically Inclined|website = Telegram|accessdate = 9 January 2016}}</ref>
=== Servers ===
Telegram Messenger LLP has servers in a number of countries throughout the world to improve the response time of their service.<ref>{{cite web|trans_title=Telegram, the chat that competes with WhatsApp|place=[[Uruguay|UY]]|url=http://www.elpais.com.uy/vida-actual/que-telegram-chat-que-compite.html|work=El País|title=Telegram, el chat que compite con Whatsapp|language=es|accessdate=8 January 2016}}</ref> Telegram's server-side software is closed-source and proprietary. Pavel Durov has said that it would require a major architectural redesign of the server-side software to connect independent servers to the Telegram cloud.<ref>{{cite web|title = Pavel Durov, creador de Telegram: "Ninguna aplicación es 100% segura"|url = http://www.eldiario.es/turing/moviles_y_tabletas/telegram-pavel_durov-entrevista-app-movil-seguridad_0_224677688.html|work = eldiario.es|date = 2 February 2014|accessdate = 12 February 2014|trans-title = Pavel Durov, creator of Telegram: "No application is 100% safe"|last = Rull|first = Antonio|language = es}}</ref>
=== Client apps ===
Telegram has various client apps. This list includes versions developed on official platforms backed by Telegram Messenger LLP and unofficial clients that are developed by the community. The source code of all official Telegram clients (and some of the unofficial clients) is [[open source]] and released under the [[GNU General Public License|GNU General Public Licence]] {{Nowrap|version 2}} or 3.
{| class="wikitable sortable"
|-
! Name !! Platform(s) !! Official !! Source code license !! Support for secret chats !! Notes
|-
| Telegram || [[macOS]] || {{yes}} || {{free|GPLv2}}<ref>{{cite web|author=overtake|url=https://github.com/overtake/telegram|title=overtake/telegram|website=GitHub|date=1 December 2015|accessdate=8 January 2016}}</ref> || {{yes}} ||
|-
| Telegram Desktop || [[Windows NT]] (traditional, [[portable application|portable]] and [[Universal Windows Platform apps|UWP app]]), macOS, and [[Linux]] || {{yes}} || {{free|GPLv3 with OpenSSL exception}}<ref>{{cite web|author=telegramdesktop|url=https://github.com/telegramdesktop/tdesktop|title=telegramdesktop/tdesktop|website=GitHub|date=|accessdate=8 January 2016}}</ref> || {{no}} ||
|-
| Cutegram<ref>{{cite web|last1=Sauerland|first1=Andreas|title=Cutegram: So verwenden Sie die Chat-App am PC|url=http://www.computerbild.de/artikel/cb-News-Handy-Telegram-Cutegram-am-PC-nutzen-11501268.html|website=Computer Bild|publisher=Axel Springer|accessdate=25 April 2016|language=German|date=21 March 2015}}</ref> || Windows, macOS, and Linux || {{no}} || {{free|GPLv3}}<ref>{{cite web|author=Aseman Land|url=https://github.com/Aseman-Land/Cutegram|title=Aseman-Land/Cutegram|website=GitHub|date=|accessdate=8 January 2016}}</ref> || {{Yes}} || Based on [[Qt (software)|Qt]].<ref>{{cite web|url=http://aseman.co/en/products/cutegram/|title=Cutegram|author=Aseman Land|publisher=Aseman|date=|accessdate=8 January 2016}}</ref>
|-
| Telegram CLI<ref name="Lokot-2016-05-02"/><ref name="tg-cli" /> || Linux, [[FreeBSD]] and macOS || {{No}}<ref name=Apps /> || {{free|GPLv2}}<ref name="tg-cli">{{cite web|author=vysheng|url=https://github.com/vysheng/tg|title=vysheng/tg|website=GitHub|date=|accessdate=9 January 2016}}</ref> || {{Yes}} || Command-line interface for Telegram.
|-
| MadelineProto<ref name="MadelineProto" /> || Linux, [[FreeBSD]], Windows and macOS || {{No}}<ref name=Apps /> || {{free|AGPLv3}}<ref name="MadelineProto">{{cite web|author=danog|url=https://github.com/danog/MadelineProto|title=danog/MadelineProto|website=GitHub|date=|accessdate=25 August 2017}}</ref> || {{Yes}} || Telegram library with support for secret chats and telegram voice calls
|-
| Telegram Messenger || [[iOS]] 6 or later || {{yes}} || {{free|GPLv2 or later}}<ref name=Apps /><ref>{{cite web|author=peter-iakovlev|url=https://github.com/peter-iakovlev/Telegram|title=peter-iakovlev/Telegram|website=GitHub|date=18 November 2015|accessdate=8 January 2016}}</ref> || {{Yes}} || Launched in August 2013 for [[iPhone]] and [[iPod Touch]] and relaunched in July 2014 with support for [[iPad]].<ref>{{cite web|language=es|url=http://www.cnet.com/es/noticias/telegram-se-actualiza-para-la-pantalla-del-ipad/|trans_title=Telegram updated for the iPad screen|title=Telegram se actualiza para la pantalla del iPad|publisher=Cnet}}</ref>
|-
| Telegram || [[Android (operating system)|Android]] 2.3 or later || {{yes}} || {{free|GPLv2 or later}}<ref name=Apps /><ref>{{cite web|author=DrKLO|url=https://github.com/DrKLO/Telegram|title=DrKLO/Telegram|website=GitHub|date=|accessdate=8 January 2016}}</ref> || {{Yes}} || Supports [[tablet computer|tablets]]<ref>{{cite web|url=http://www.newsslash.com/n/2288-telegram-anleitung-so-benutzt-man-den-messenger|language=de|title=Telegram-Anleitung: So benutzt man den Messenger|publisher=Newsslash}}</ref> and [[Android Wear]] smart watches.<ref>{{cite web|language=es|trans_title=Telegram updated with Android Wear compatibility|url=http://sevilla.abc.es/mobility/noticia/android/noticias-android/telegram-se-actualiza-con-compatibilidad-para-android-wear/|title=Telegram se actualiza con compatibilidad para Android Wear|publisher=ABC|place=Sevilla|accessdate=7 December 2014}}</ref>
|-
| Telegram Messenger || [[Windows Phone]] || {{yes}} || {{free|GPLv2 or later}}<ref name=Apps>{{cite web|url=https://telegram.org/apps|website=Telegram.org|title=Telegram Apps|accessdate=9 January 2016}}</ref> || {{Yes}} ||
|-
| Telegram || [[Firefox OS]] || {{yes}} || {{free|GPLv3}}<ref name="gh-webogram">{{cite web|author=Igor Zhukov|url=https://github.com/zhukov/webogram|title=zhukov/webogram|website=GitHub|date=|accessdate=8 January 2016}}</ref>|| {{No}} || Based on Webogram.
|-
| Telegram || [[Google Chrome]] and [[Chrome OS]] || {{yes}} || {{free|GPLv3}}<ref name="gh-webogram" />|| {{No}} ||
|-
| Telegram{{third-party inline|date=April 2016}} || [[Ubuntu Touch]] || {{no}} || {{free|GPLv2}}<ref name="ubuntu-telegram-app">{{cite web|url=https://launchpad.net/telegram-app|title=Telegram app|website=Launchpad}}</ref> || {{Yes}} ||
|-
| Sailorgram{{third-party inline|date=April 2016}} || [[Sailfish OS]] || {{no}} || {{free|GPLv3}}<ref name="Sailfish Telegram App">{{cite web|url=https://openrepos.net/content/dax/sailorgram|title=Telegram app|website=OpenRepos}}</ref> || {{Yes}} || Based on Cutegram.
|-
|Telegram-Purple<ref>{{Cite web|url=https://github.com/majn/telegram-purple|title=majn/telegram-purple|website=GitHub|access-date=2016-09-30}}</ref>
|Windows, macOS, and Linux
|{{No}}
|{{free|GPLv2}}
|{{Yes}}
|Plugin for Pidgin, Adium, Finch and other Libpurple-based messengers
|-
|Unigram<ref>{{Cite web|url=https://www.microsoft.com/en-us/store/p/unigram-preview/9n97zckpd60q|title=Unigram Preview - Microsoft Store|website=Microsoft Store|language=en-us|access-date=2017-04-20}}</ref><ref>{{Cite web|url=https://github.com/UnigramDev/Unigram|title=UnigramDev/Unigram|website=GitHub|language=en|access-date=2017-04-20}}</ref>
|[[Universal Windows Platform]]
|{{No}}
|{{Free|GPLv3}}
|{{No}}
|
|}
Users can also access Telegram's cloud-based messages via an official [[web browser]] interface called Telegram Web (aka Webogram). Users can share images, files and [[emoticon]]s with previously-added contacts; this works in most modern browsers, such as [[Firefox]], [[Safari (web browser)|Safari]], and [[Google Chrome]].<ref name=Apps /><ref name="gh-webogram" />
=== APIs ===
Telegram has public [[Application programming interface|APIs]] with which developers can access the same functionality as Telegram's official apps to build their own messaging applications.<ref>{{Cite news|url=http://www.programmableweb.com/news/can-telegram-beat-whatsapp-public-api/2014/03/03|title=Can Telegram Beat WhatsApp with a Public API?|last=Roble|first=Patricio|date=3 March 2014|work=ProgrammableWeb|access-date=|via=}}</ref> In February 2015, creators of the unofficial Whatsapp+ client released the Telegram Plus app, later renamed to Plus Messenger, after their original project got a [[Cease and desist|cease-and-desist order]] from [[WhatsApp]].<ref>{{Cite news|url=http://www.androidpolice.com/2015/02/27/whatsapp-developer-releases-telegram-forced-drop-first-project/|title=WhatsApp+ Developer Releases Telegram+ After Being Forced To Drop The First Project|last=King|first=Bertel|date=27 February 2015|work=AndroidPolice|access-date=|via=}}</ref><ref>{{Cite web|url=http://www.androidpolice.com/2015/01/21/whatsapp-now-officially-dead-receiving-cease-desist-real-whatsapp/|title=WhatsApp+ Is Now Officially Dead After Receiving A Cease And Desist From The Real WhatsApp|date=21 January 2015|website=Android Police|access-date=}}</ref> In September 2015, [[Samsung]] released a messaging application based on these APIs.<ref>{{cite web|url =http://news.samsung.com/global/socializer-messenger-app-offers-a-new-approach-to-messaging|title = Socializer Messenger App Offers a New Approach to Messaging|date = 14 September 2015}}</ref>
Telegram also offers an API that allows developers to create [[IM bot|bots]], which are accounts controlled by programs.<ref>{{Cite web|url=http://www.programmableweb.com/news/telegram-launches-bot-api-and-platform/2015/06/29|title=Telegram Launches Bot API and Platform|last=Carter|first=Eric|date=27 June 2015|website=ProgrammableWeb}}</ref><ref>{{Cite web|url=https://techcrunch.com/2015/06/24/telegrams-new-platform-lets-developers-create-smart-message-bots-with-multiple-uses/|title=Telegram’s New Platform Lets Developers Create Smart Message Bots With Multiple Uses|last=Butcher|first=Mike|date=24 June 2015|website=TechCrunch}}</ref> In February 2016, ''[[Forbes]]'' launched an [[Artificial intelligence|AI]]-powered news bot that pushes popular stories to subscribers and replies to search queries with relevant articles.<ref>{{Cite web|url=https://www.forbes.com/sites/bruceupbin/2016/02/23/introducing-the-forbes-newsbot-on-telegram/#270d46ef3117|title=Introducing The Forbes Newsbot on Telegram|last=Ubpin|first=Bruce|date=23 February 2016|website=Forbes}}</ref> [[TechCrunch]] launched a similar bot in March 2016.<ref>{{Cite web|url=https://techcrunch.com/2016/03/15/check-out-the-new-ai-powered-techcrunch-news-bot-on-telegram-messenger/|title=Check out the new AI-powered TechCrunch news bot on Telegram messenger|last=Bernard|first=Travis|date=15 March 2016|website=TechCrunch}}</ref>
== Reception ==
{{POV section|date=April 2017}}
=== Security ===
Cryptography experts have expressed both doubts and criticisms on Telegram's MTProto encryption scheme, saying that deploying [[Snake oil (cryptography)|home-brewed and unproven cryptography]] may render the encryption vulnerable to bugs that potentially undermine its security, due to a lack of scrutiny.<ref name="cpj-2016-05-31" /><ref>{{harvnb|Jakobsen|Orlandi|2015}}</ref><ref name="Cox-2015">{{cite web|last1=Cox|first1=Joseph|title=Why You Don't Roll Your Own Crypto|url=http://motherboard.vice.com/read/why-you-dont-roll-your-own-crypto|website=Motherboard|publisher=[[Vice Media]]|accessdate=11 December 2015|date=10 December 2015}}</ref> It has also been suggested that Telegram did not employ developers with sufficient expertise or credibility in this field.<ref>{{cite web|last1=Turton|first1=William|title=Cryptography expert casts doubt on encryption in ISIS' favorite messaging app|url=http://www.dailydot.com/politics/telegram-isis-encryption-cryptography/|website=The Daily Dot|accessdate=11 December 2015|date=19 November 2015}}</ref>
Critics have also disputed claims by Telegram that it is "more secure than mass market messengers like WhatsApp and [[Line (application)|Line]]",<ref name="how-secure"/> because WhatsApp applies end-to-end encryption to all of its traffic by default and uses a protocol that has been "reviewed and endorsed by leading security experts", while Telegram does neither and insecurely stores all messages, media and contacts in their cloud.<ref name="RT-2015-12-20">{{cite web|title=Snowden doubts security of Telegram|url=https://www.rt.com/news/326565-snowden-durov-security-telegram/|website=RT|publisher=RT|accessdate=11 February 2017|date=20 December 2015}}</ref><ref name="cpj-2016-05-31"/><ref name="Turton-2016-06-24">{{cite web|last1=Turton|first1=William|title=Why You Should Stop Using Telegram Right Now|url=https://gizmodo.com/why-you-should-stop-using-telegram-right-now-1782557415|website=Gizmodo|publisher=Gawker Media|accessdate=7 July 2016|date=24 June 2016}}</ref> Since July 2016, Line has also applied end-to-end encryption to all of its messages by default.<ref name="Sawers-2016-06-30">{{cite web|last1=Sawers|first1=Paul|title=Ahead of IPO, mobile messaging giant Line introduces end-to-end encryption by default|url=https://venturebeat.com/2016/06/30/ahead-of-ipo-mobile-messaging-giant-line-introduces-end-to-end-encryption-by-default/|website=VentureBeat|accessdate=10 September 2016|date=30 June 2016}}</ref>
On 26 February 2014, the [[Germany|German]] [[consumer organization]] [[Stiftung Warentest]] evaluated several data-protection aspects of Telegram, along with other popular instant-messaging clients. Among the aspects considered were: the security of the data transmission, the service's terms of use, the accessibility of the source code and the distribution of the app. Telegram was rated 'critical' (''{{Lang|de|kritisch}}'') overall. The organization was favorable to Telegram's secure chats and partially open source code, but criticized the mandatory transfer of contact data to Telegram's servers and the lack of an imprint or address on the service's website. It noted that while the message data is encrypted on the device, it could not analyse the transmission due to a lack of source code.<ref>{{Cite web|url=https://www.test.de/WhatsApp-und-Alternativen-Datenschutz-im-Test-4675013-0/|title=WhatsApp und Alternativen: Datenschutz im Test|date=26 February 2014|website=[[Stiftung Warentest]]|language=de|trans-title=WhatsApp and alternatives: data protection tested|access-date=2 March 2016}}</ref>
The [[Electronic Frontier Foundation]] (EFF) listed Telegram on its "Secure Messaging Scorecard" in February 2015. Telegram's default chat function received a score of 4 out of 7 points on the scorecard. It received points for having communications encrypted in transit, having its code open to independent review, having the security design properly documented, and having completed a recent independent security audit. Telegram's default chat function missed points because the communications were not encrypted with keys the provider didn't have access to, users could not verify contacts' identities, and past messages were not secure if the encryption keys were stolen. Telegram's optional secret chat function, which provides end-to-end encryption, received a score of 7 out of 7 points on the scorecard.<ref name="EFF-scorecard-v1">{{cite web|url=https://www.eff.org/node/82654 |title=Secure Messaging Scorecard |date=17 February 2015|website=Electronic Frontier Foundation |accessdate=20 July 2016}}</ref> The EFF said that the results "should not be read as endorsements of individual tools or guarantees of their security", and that they were merely indications that the projects were "on the right track".<ref name="EFF-scorecard-v1"/>
In December 2015, two researchers from [[Aarhus University]] published a report in which they demonstrated that MTProto does not achieve [[Ciphertext indistinguishability#Indistinguishability under chosen ciphertext attack.2Fadaptive chosen ciphertext attack .28IND-CCA1.2C IND-CCA2.29|indistinguishability under chosen-ciphertext attack]] (IND-CCA) or [[authenticated encryption]].<ref>{{harvnb|Jakobsen|Orlandi|2015|p=6}}</ref> The former means that it is possible to turn any [[ciphertext]] into a different ciphertext that decrypts to the same message. The researchers stressed that the attack was of a theoretical nature and they "did not see any way of turning the attack into a full plaintext-recovery attack". Nevertheless, they said they saw "no reason why [Telegram] should use a less secure encryption scheme when more secure (and at least as efficient) solutions exist".<ref name="Jakobsen-2015-p1">{{harvnb|Jakobsen|Orlandi|2015|p=1}}</ref> The Telegram team responded that the flaw does not affect message security<ref>{{cite web|title=FAQ for the Technically Inclined: What about IND-CCA?|url=https://core.telegram.org/techfaq#what-about-ind-cca|website=Telegram|publisher=Telegram|accessdate=25 March 2017}}</ref> and that "a future patch would address the concern".<ref>{{cite web|last1=Clary|first1=Grayson|title=The Flaw in ISIS's Favorite Messaging App|url=https://www.theatlantic.com/technology/archive/2016/01/isiss-favorite-messaging-app-has-a-security-problem/422460/|website=The Atlantic|publisher=The Atlantic|accessdate=25 March 2017}}</ref>
In April 2016, accounts of several Russian opposition members were hijacked by intercepting the SMS messages used for login authorization.<ref name="Lokot-2016-05-02"/> In response, Telegram recommended using the optional two-factor authentication feature.<ref name="Lokot-2016-05-02"/> In May 2016, the [[Committee to Protect Journalists]] and Nate Cardozo, senior staff attorney at Electronic Frontier Foundation, recommended against using Telegram because of "its lack of end-to-end encryption [by default] and its use of non-standard MTProto encryption protocol, which has been publicly criticized by cryptography researchers, including [[Matthew D. Green|Matthew Green]]".<ref name="cpj-2016-05-31">{{cite web|title=Why Telegram's security flaws may put Iran's journalists at risk|url=https://cpj.org/blog/2016/05/why-telegrams-security-flaws-may-put-irans-journal.php|publisher=Committee to Protect Journalists|accessdate=20 July 2016|date=31 May 2016}}</ref>
In June 2017, Pavel Durov claimed publicly that U.S. intelligence agencies tried to bribe the company's developers to weaken Telegram's encryption or install a backdoor during their visit to the U.S. in 2016.<ref>{{cite news|title=Telegram founder: U.S. intelligence agencies tried to bribe us to weaken encryption|url=https://news.fastcompany.com/telegram-founder-us-intelligence-agencies-tried-to-bribe-us-to-weaken-encryption-4040876|accessdate=15 June 2017|work=FastCo News|date=15 June 2017}}</ref><ref>{{cite web|last1=Leyden|first1=John|title=Telegram chat app founder claims Feds offered backdoor bribe|url=https://www.theregister.co.uk/2017/06/14/telegram_boss_backdoor_offer_claim/|website=The Register|publisher=Situation Publishing|accessdate=15 June 2017|date=14 June 2017}}</ref>
=== Cryptography contests ===
Telegram has organized two cryptography contests to challenge its own security. Third parties were asked to break the service's cryptography and disclose the information contained within a secret chat between two computer-controlled users. A reward of respectively {{US$|200000}} and {{US$|300000}} was offered. Both of these contests expired with no winners.<ref>{{Cite web|url = https://telegram.org/blog/winter-contest-ends|title = Winter Contest Ends|date = 2 March 2014|accessdate = 24 October 2015|website = Telegram}}</ref><ref>{{Cite web|url = https://telegram.org/blog/cryptocontest-ends|title = Crypto Contest Ends|date = 11 February 2015|accessdate = 24 October 2015|website = Telegram}}</ref> Security researcher [[Moxie Marlinspike]] and commenters on ''[[Hacker News]]'' criticized the first contest for being rigged or framed in Telegram's favor and said that Telegram's statements on the value of these contests as proof of the cryptography's quality are misleading.<ref>{{cite web|url = http://thoughtcrime.org/blog/telegram-crypto-challenge/|title = A Crypto Challenge for the Telegram Developers|first = Moxie|last = Marlinspike|date = 19 December 2013|work = Thought Crime|accessdate = 2 March 2014|authorlink = Moxie Marlinspike}}</ref><ref>{{cite web|url = http://tech.eu/news/telegram-protocol-cracking-contest/|title = Cracking contest: first one who breaks Telegram gets $200,000 in bitcoins (but really, nobody wins)|first = Robin|last = Wauters|date = 19 December 2013|accessdate = 2 March 2014|website = Tech.eu}}</ref><ref>{{Cite web|url = http://www.cryptofails.com/post/70546720222/telegrams-cryptanalysis-contest|title = Telegram's Cryptanalysis Contest|date = 19 December 2013|accessdate = 24 October 2015|website = Crypto Fails|last = Hornby|first = Taylor}}</ref>
=== Censorship ===
[[File:Countries where Telegram is blocked.svg|thumb|400px|{{legend|#8E0000|Completely blocked|border=1px #555 solid}}
{{legend|#D34343|Blocked partially (some ISPs or audio traffic)|border=1px #555 solid}}]]
Telegram was open and working in Iran without any VPN or other circumvention methods in May 2015.<ref>{{cite web|url=http://www.tasnimnews.com/fa/news/1394/02/21/736788/%D8%AA%D9%84%DA%AF%D8%B1%D8%A7%D9%85-%D9%81%DB%8C%D9%84%D8%AA%D8%B1-%D9%86%D8%B4%D8%AF%D9%87-%D8%A7%D8%B3%D8%AA|publisher=Tasnim News Agency|location=Tehran|quote=Though it is claimed by many that the Telegram is banned, but it is operating normally in Iran.|date=11 May 2015|accessdate=29 October 2015|title=تلگرام فیلتر نشده است|language=fa}}</ref> In August 2015, the [[Ministry of Information and Communications Technology of Iran|Iranian Ministry of ICT]] asserted that Telegram had agreed to restrict some of its bots and sticker packs in Iran at the request of the Iranian government.<ref name="globalvoices-08-2015" /> According to an article published on ''[[Global Voices Online|Global Voices]]'', these features were being used by Iranians to "share satirical comments about the Iranian government". The article also noted that "some users are concerned that Telegram's willingness to comply with Iranian government requests might mean future complicity with other Iranian government censorship, or even allow government access to Telegram's data on Iranian users".<ref name="globalvoices-08-2015">{{cite web|last1=Alimardani|first1=Mahsa|title=Is Telegram's Compliance with Iran Compromising the Digital Security of Its Users?|url=https://advocacy.globalvoicesonline.org/2015/08/28/is-telegrams-compliance-with-iran-compromising-the-digital-security-of-its-users/|publisher=Global Voices Online|accessdate=30 August 2015|date=28 August 2015}}</ref> Telegram has stated that all Telegram chats are private territory and that they do not process any requests related to them. Only requests regarding public content (bots and sticker packs) will be processed.<ref>{{cite web|url=https://telegram.org/faq#q-there-39s-illegal-content-on-telegram-how-do-i-take-it-down|publisher=Telegram|title=Telegram FAQ|accessdate=14 September 2015}}</ref> In May 2016, the Iranian government asked all messaging apps, including Telegram to move all Iranian users' data to Iranian servers.<ref>{{Cite web|url=https://techcrunch.com/2016/05/30/iran-forces-messaging-apps-to-move-data-to-iranian-servers/|title=Iran forces messaging apps to move data to Iranian servers|last=Dillet|first=Romain|website=TechCrunch|access-date=31 May 2016}}</ref> On 20 April 2017, the Iranian government completely blocked Telegram’s new voice calls, a service that allows individuals to make calls via secure, end-to-end encryption, and keep their conversations private<ref>https://www.iranhumanrights.org/2017/04/iranian-judiciary-blocks-popular-telegram-apps-new-voice-call-service/</ref>.
In July 2015, it was reported that China blocked access to Telegram Messenger. According to state-owned [[People's Daily]], Chinese human rights lawyers used Telegram to criticize the [[Chinese Government]] and the [[Communist Party of China]].<ref>https://www.hongkongfp.com/2015/07/13/china-blocks-telegram-messenger-blamed-for-aiding-human-rights-lawyers/</ref>
In June 2016, it was found that some ISPs in [[Bahrain]] had started to block Telegram.<ref>{{Cite news|url=https://bahrainwatch.org/blog/2016/06/28/leading-bahraini-isps-are-blocking-telegram-traffic/|title=Leading Bahraini ISPs are Blocking Telegram Traffic|date=2016-06-28|work=Bahrain Watch|access-date=2017-08-08|language=en-US}}</ref> In June 2017 the service faced serious pressure from Russian regulator [[Roscomnadzor]], who tried to force Telegram to get registered in the official telecommunication services roster, which implies serious liability for a registered party. After week-long negotiations and seemed imminent blockage of the service, the conflict ceased after the some high officials having pulled the strings on the regulator. On 14 July 2017, eleven domain name servers related to Telegram were banned by the [[Indonesia|Indonesian]] Communication and Information Ministry with the possibility of closing all Telegram applications in Indonesia if Telegram did not make a standard operating procedure to maintain content that was considered unlawful in the apps.<ref>{{cite web |url=http://www.riaupos.co/print.php?cat=11&id=156454 |title=Tak Perlu Blokir Telegram, Pengamat Sarankan Cara Ini kepada Mekominfo |author=Boy Riza Utama |date=July 15, 2017}}</ref> In August 2017, Indonesian Government has opened full access of Telegram, after Telegram has made self censorship about negative contents mainly radicalism and terrorism. Telegram said that about 10 channels/groups have been deleted from Telegram everyday due to are categorized as negative contents.<ref>{{cite web |url=http://www.tribunnews.com/nasional/2017/08/10/telegram-setiap-hari-hapus-10-grup-di-indonesia-terkait-konten-radikal-dan-terorisme |title=Telegram Setiap Hari Hapus 10 Grup Di Indonesia Terkait Konten Radikal dan Terorisme |date=August 10, 2017}}</ref>
=== Use by terrorists ===
In September 2015, in response to a question about the use of Telegram by [[Islamic State of Iraq and the Levant]] (ISIS), Pavel Durov stated: "I think that privacy, ultimately, and our right for privacy is more important than our fear of bad things happening, like [[terrorism]]."<ref>{{Cite web|title = Telegram Now Seeing 12BN Daily Messages, Up From 1BN In February|url = https://techcrunch.com/2015/09/21/telegram-now-seeing-12bn-daily-messages-up-from-1m-in-february/|website = TechCrunch|accessdate = 19 November 2015|first = Natasha|last = Lomas}}</ref> ISIS has recommended Telegram to its supporters and members<ref name=":1">{{cite web|url=http://www.cnn.com/2016/08/01/europe/france-church-attack-telegram/index.html|title=Killers of French priest met 4 days before attack|first1=Margot |last1=Haddad |first2=Tim |last2=Hume|publisher=cnn.com}}</ref><ref>{{cite web |url=http://tjournal.ru/p/telegram-jihadi |title=Павел Дуров прокомментировал для CNN историю с подготовкой теракта через Telegram |website =TJournal.ru |first=Gennady |last=Zavolokyn |language=ru |accessdate =20 October 2015}}</ref><ref>{{cite web|url=http://www.csoonline.com/article/3004648/security-awareness/after-paris-isis-moves-propaganda-machine-to-darknet.html|title=After Paris, ISIS moves propaganda machine to Darknet|author=Steve Ragan|date=16 November 2015|work=CSO Online}}</ref> and in October 2015 they were able to double the number of followers of their official channel to 9,000.<ref>{{cite web|url=https://news.yahoo.com/isis-telegram-channel-doubles-followers-172356843.html|title=Isis Telegram channel doubles followers to 9,000 in less than 1 week|date=12 October 2015|work=Yahoo News}}</ref> In November 2015, Telegram announced that it had blocked 78 public channels operated by ISIS, which were used for spreading propaganda and mass communication.<ref>{{Cite web|title = Encrypted messaging app Telegram shuts down Islamic State propaganda channels|url = http://www.telegraph.co.uk/technology/news/12004892/Encrypted-messaging-app-Telegram-shuts-down-Islamic-State-propaganda-channels.html|website = Telegraph.co.uk|accessdate = 19 November 2015}}</ref><ref>{{Cite web|title = One app maker has shut down almost 80 secret channels used by ISIS to communicate|url = http://www.businessinsider.com/telegram-blocks-isis-channels-2015-11|website = Business Insider|accessdate = 19 November 2015}}</ref><ref>{{Cite news|url=https://www.independent.co.uk/life-style/gadgets-and-tech/news/telegram-knew-isis-communicate-paris-pavel-durov-a6742126.html|title=Telegram founder knew Isis used the app to communicate before Paris attacks|date=2015-11-20|work=The Independent|access-date=2017-04-24|language=en-GB}}</ref> Telegram stated that it would block public channels and bots that are related to terrorism, but it would not honor "politically-motivated censorship" based on "local restrictions on freedom of speech" and that it allowed "peaceful expression of alternative opinions."<ref>{{Cite web|title = Secretive messaging app used by IS takes down posts|url = https://www.cnbc.com/2015/11/19/telegram-the-messaging-app-used-by-isis-takes-down-78-posts.html|website = CNBC|accessdate = 19 November 2015}}</ref> Telegram's usage for ISIS's propaganda has reignited the encryption debate and encrypted messaging applications have faced new scrutiny.<ref>{{Cite news|title = Encrypted Messaging Apps Face New Scrutiny Over Possible Role in Paris Attacks|url = https://www.nytimes.com/2015/11/17/world/europe/encrypted-messaging-apps-face-new-scrutiny-over-possible-role-in-paris-attacks.html|newspaper = [[The New York Times]]|date = 16 November 2015|access-date = 19 November 2015|first = David|last = Sanger|first2 = Nicole|last2 = Perlroth}}</ref><ref>{{cite web|last1=Foges|first1=Clare|title=Why is Silicon Valley helping the tech-savvy jihadists?|url=http://www.telegraph.co.uk/technology/12008689/Why-is-Silicon-Valley-helping-the-tech-savvy-jihadists.html|website=The Telegraph|accessdate=9 December 2015}}</ref> It has also led to [[Tabloid journalism|tabloids]] misunderstanding Telegram as a "[[jihadism|jihadi]] messaging app".<ref>{{cite news |last=Campbell |first=Scott |date=26 July 2016 |title=ISIS warn London 'next to be attacked' as UK churches put on terror alert after French priest murder |url=http://www.mirror.co.uk/news/world-news/isis-warn-london-next-attacked-8500399 |newspaper=[[Daily Mirror]] |quote=Images threatening attacks in London and other major world capitals have been posted on jihadi messaging app Telegram |access-date=15 December 2016}}</ref>
In August 2016, [[France|French]] anti-terrorism investigators asserted that the two ISIS-directed [[Jihadism|Jihadists]] who [[2016 Normandy church attack|fatally cut the throat of a priest]] in [[Saint-Étienne-du-Rouvray]] in [[Normandy]], France, and videoed the murder, had communicated via Telegram and "used the app to coordinate their plans for the attack". ISIS's media wing subsequently posted a video on Telegram, showing the pair pledging allegiance. A [[CNN]] news report stated that Telegram "has become known as a preferred means of communication for the Sunni terror group ISIS and was used by the ISIS cell that plotted the [[November 2015 Paris attacks|Paris terror attacks in November]]".<ref name=":1" />
In June 2017, the Russian communications regulator, [[Roscomnadzor]], hinted at the possibility of blocking Telegram in Russia due to its usage by terrorists.<ref>(in Russian) {{cite web|last1=Martynov|first1=Kirill|title=Занять Телеграм|url=https://www.novayagazeta.ru/articles/2017/06/24/72903-zanyat-telegram|website=Novaya Gazeta|accessdate=26 June 2017}}</ref>
According to Director General of Application and Informatics of the [[Ministry of Communication and Informatics (Indonesia)|Ministry of Communication and Informatics]], Semuel Abrijani Pangerapan, eleven DNS of Telegram was blocked (see [[Telegram_(messaging_service)#Censorship|sub-section Censorship]] above) because there are many canals that contain propaganda of radicalism and terrorism, how to assemble bombs, "disturbing images", and other things that are against the Indonesian law.<ref>{{cite news|last1=Widiartanto|first1=Yoga Hastyadi|title=Ini Alasan Pemerintah Blokir Telegram|trans-title=This is the Reason Why the Government Blocks Telegram|url=http://tekno.kompas.com/read/2017/07/14/20495927/ini-alasan-resmi-pemerintah-blokir-telegram|accessdate=15 July 2017|work=[[Kompas]]|date=14 July 2017|language=id}}</ref>
== See also ==
{{Portal|Information technology|Cryptography|Telecommunications|Free software|Freedom of speech|Terrorism}}
* [[Comparison of instant messaging clients]]
* [[List of virtual communities with more than 100 million active users]]
* [[Internet privacy]]
* [[Secure instant messaging]]
{{clear}}
== References ==
{{reflist|30em}}
==Further reading==
{{Refbegin}}
* {{cite web|url=https://eprint.iacr.org/2015/1177.pdf|title=On the CCA (in)security of MTProto|last1=Jakobsen|first1=Jakob|last2=Orlandi|first2=Claudio|date=8 December 2015|website=Cryptology ePrint Archive|publisher=International Association for Cryptologic Research (IACR)|format=PDF|archive-url=|archive-date=|dead-url=|accessdate=11 December 2015|ref={{harvid|Jakobsen|Orlandi|2015}}}}
* {{Cite conference|last1=Rottermanner|first1=Christoph|last2=Kieseberg|first2=Peter|last3=Huber|first3=Markus|last4=Schmiedecker|first4=Martin|last5=Schrittwieser|first5=Sebastian|date=December 2015|title=Privacy and Data Protection in Smartphone Messengers|url=https://www.sba-research.org/wp-content/uploads/publications/paper_drafthp.pdf|format=PDF|conference=Proceedings of the 17th International Conference on Information Integration and Web-based Applications & Services (iiWAS2015)|publisher=ACM International Conference Proceedings Series|volume=|pages=|isbn=978-1-4503-3491-4|accessdate=18 March 2016|ref={{harvid|Rottermanner|Kieseberg|Huber|Schmiedecker|2015}}|via=}}
{{Refend}}
== External links ==
{{Commonscatinline|Telegram Messenger}}
* {{Official website}}
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