Telegram

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Telegram

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Basic data

developer Telegram Messenger LLP (until January 2019)
Publishing year 2013
Current  version 7.0.0 ( Android )
August 14, 2020

6.1.1 (Android open source version)
May 9, 2020

7.0.0 ( iOS )
August 14, 2020

7.0.0 ( macOS )
August 14, 2020

2.3.0 ( Windows - Desktop )
August 14, 2020

2.2.0 ( Linux desktop)
July 26, 2020

2.2.0 (macOS desktop)
July 26, 2020

3.4 ( Windows Mobile )
February 4, 2014

0.5.7.1 ( Google Chrome )
March 8, 2019

0.5.4 ( Firefox OS )
June 12, 2016

1.4.1 ( FreeBSD )
December 27, 2016

operating system Android , iOS , watchOS , iPadOS , Windows Phone / Windows 8 Mobile , Windows 10 Mobile , Firefox OS , Sailfish OS , Ubuntu Touch , Windows , macOS , Linux , FreeBSD
programming language C ++
category Instant messaging
License GNU GPL (client), proprietary (server)
German speaking Yes
Others 400 million monthly active usersTemplate: Infobox software / maintenance / other
telegram.org

Telegram is a free instant messaging - service for use on smartphones , tablets , Smart Watches and PCs. Telegram users can exchange text messages, voice messages, photos, videos and documents and use voice and video telephony with other Telegram users.

The chats can be cloud-based (standard) or alternatively as “secret chats” directly between the end devices. With cloud chats , users can synchronize and access their messages and files on multiple devices, for example on their desktop, tablet or smartphone. With the optional “ secret chats ”, the messages and files are only saved on those two end devices of the users from which the chat was started; synchronization across multiple devices of a user is not possible. They are only possible between two users, not in groups or channels and are not supported by all clients, especially not by the official desktop and WEB clients. Further information can be found under Security of Chats .

The base of the development team is according to their own information in Dubai , but no imprint is given on the website. The founder Pawel Durow and his employees see themselves as digital nomads .

Due to the security of the service, it is used by numerous activist groups, right-wing extremists and terrorists, among others, as well as for sharing child pornography and for pump-and-dump activities on cryptocurrencies . As a result, the app often receives a lot of media attention around the world when national and international criminal cases are uncovered in which the app was the main means of communication.

History and background

Telegram was founded in 2013 by brothers Nikolai and Pawel Durov , who had already founded the most widely used Russian social network Vk.com . Telegram Messenger LLP ( partnership under British / US law) claims to be an independent non-profit company . According to the Telegram website, the development team is in Dubai after trying locations such as Russia, Berlin, London and Singapore, and according to its own information is not associated with Vk.com or Russia. The telegram LLP is registered to the London address of a company that is headquartered in the Seychelles has. This company is owned by two companies based in the Virgin Islands and Belize . However, Telegram Messenger LLP was dissolved by Pavel Durow in January 2019. According to press reports, Telegram has employees in St. Petersburg.

Nikolai Durov wrote the MTProto protocol on which Telegram is based. His brother Pawel provides the financial basis. Telegram is a free, ad-free app that may later be funded through donations. The service competes with many other mobile instant messengers . As a result of the WhatsApp takeover by Facebook , Telegram also established itself as one of the most successful free instant messenger alternatives for all common platforms.

The code of the Telegram clients - but not the server - is largely publicly available and licensed under the GNU GPL . An open programming interface (API) is offered for the server . Based on this, a number of alternative clients were published, for example the Plus Messenger, which was initially published in early 2015 under the name Telegram Plus as the immediate successor to WhatsApp Plus, and the Socializer Messenger from Samsung , which is to replace the ChatON service, which was discontinued at the beginning of 2015 .

Telegram reported in February 2014 that over five million new users had registered. This should be directly related to the purchase of WhatsApp by Facebook. Something similar happened to Telegram a year later, in February 2015, when a judge in Brazil ordered WhatsApp to be blocked nationwide. Telegram reported an increase of over 2.5 million users within a very short time. In 2016, Telegram was way ahead of its competitors Signal (3.62 million) and Wickr (3.8 million) with almost 50 million new app downloads , but far behind WhatsApp with around 225 million downloads in 2016.

In May 2015, Pavel Durov announced that Telegram has 62 million monthly active users who send 2 billion messages a day. As of February 2016, Telegram said it had 100 million monthly active users and delivers 15 billion messages per day. In March 2018, the development team announced that they had reached the limit of 200 million users per month and exceeded the limit of 400 million users on April 24, 2020.

State efforts to blockade

Since the “normal” in contrast to the “secret” messages and also the link to the contacts are in principle accessible to the Telegram operators in clear text, access to the service is attractive for state actors. In order to force this, Russian authorities tried to block Telegram. There are also blockades in Iran , Indonesia and China for reasons of censorship .

Russia

Telegram is very popular with 30 million users in Russia. Dimitri Peskow , a spokesman for Putin, mentioned in 2017 in the newspaper RBK that the service was also used in the Russian government: “In the Kremlin we use Telegram for internal communication”. After the attempted blocking of Telegram from mid-April 2018, Kremlin employees were recommended to use the messenger service ICQ .

After the terrorist attack in Saint Petersburg, the Russian secret service FSB repeatedly asked Telegram to provide them with the duplicate keys for data decryption in private chats, most recently in March 2018. Critics consider this to be an advanced argument. Telegram was able to appeal against the threat of blocking the service in Russia. The Telegram founder, however, explicitly ruled out data transfer again on Twitter. As a result, on April 6, 2018, the Roskomnadzor supervisory authority filed a lawsuit against Telegram with the aim of blocking the service in Russia. The Novaya Gazeta suspected that censorship, like that of the LinkedIn network , which had been blocked in Russia since 2017 , would be circumvented, and also gave a few tips.

Telegram protest in Kaliningrad with paper planes on April 30, 2018

On April 13, 2018, a court allowed the agency to block the service because the keys were not disclosed. As a result, Telegram constantly changed the IP addresses it uses to process its data traffic, and also resorted to third-party providers such as Amazon Web Services or Google Cloud . As a result, websites of important Russian media and companies that geared their offers to their services were also blocked. In addition to Amazon and Google, the VTB bank, the state video agency Ruptly , Odnoklassniki.ru , Spotify , Viber , Mastercard , SoundCloud , FIFA  and various online gaming platforms are also affected; Finally, targeted Google services such as Gmail or Google search . The supervisory authority Roskomnadzor also blocked parts of its own website. The authority set up a hotline that those affected can contact if their Internet services have been affected. The head of the authority, Alexander Sharov , told the newspaper Vedomosti that they were in an arms race with the developers. A total of almost 19 million IP addresses were blocked, according to the operator, without any significant decline in messenger operations in Russia. Blockages were bypassed , among other things, through encrypted VPN connections or proxy servers .

Telegram co-founder Pawel Durow thanked the Russian Telegram users for their support and loyalty as well as: “Thank you, Apple, Google, Amazon, Microsoft, for not taking part in the political censorship.” In the Russian app stores of the well-known providers Telegram is still available despite being requested to remove it; The number of users has doubled within a few days. According to the authorities, only 30 percent of the users could be "locked out". Organizations such as Amnesty International and the American Civil Liberties Union called on companies such as Amazon and Google not to give in to pressure from the Russian authorities. The Russian-language Latvian-based website Meduza reports billions in losses for the Russian economy, as the blockades led to outages in online storage, geolocation, e-payment services, banking services, AI systems, mobile apps and customer services. There were also first claims for damages. Otschir Manschikow, PR chief of the Russian search engine Yandex , criticized: "The attempt to block Telegram has turned into an unexpected blow against the entire Ru-Net" and called for open competition for the Russian market. "In particular, lack of freedom and a lack of choice for users are the most dangerous consequences of the blockade." Around eight to ten thousand people protested on April 30, 2018 on Sakharov Square in Moscow against the authority's attempts to block.

In June 2020, the media regulator Roskomnadzor abandoned the ultimately failed attempts to block Telegram in Russia.

Iran

Most recently, after temporary blockades in January 2018, Telegram should be closed in mid-April after the protests in early 2018, according to a state news agency in Iran. With reference to Alaeddin Borudscherdi , chairman of the parliamentary committee for national security and foreign policy, “decisions were made at the highest political level”. The app should be replaced by the local, much less popular service Soroush . From a national security perspective, Telegram would have played “a destructive role” in recent political crises. The government of President Hassan Ruhani as well as the Ministry of Communications speak out against a blockade. Telegram currently has more than 40 or even 50 million users in Iran, Soroush, according to unconfirmed information, only 5 million, which Novaya Gazeta wrote: Telegram is the Internet in Iran, it is synonymous with the Internet itself; the traffic on Telegram makes up 40 percent of all digital traffic, also because other services such as Facebook and Twitter are blocked. According to the Iranian news agency Tasnim , the Iranian judicial authority officially ordered the ban at the end of April.

Functions

Telegram on Android , screenshot
Telegram's secret chat, screenshot (2015)

Account

Registration with Telegram takes place via a phone number that does not have to be that of the device itself. The phone number is then verified via SMS or phone call. Any number of devices can be registered with the same phone number. Content is then synchronized between these devices, except in "secret chats". The number associated with the user account can be changed at any time, and the user's contacts will automatically receive the new number. In addition, a user can set up a username that enables them to send and receive messages without revealing their own telephone number. Telegram accounts can be deleted manually at any time, by default automatically after six months of inactivity; however, this can be changed in the settings by the user to one, three or twelve months.

Web interface

In addition to the clients that can be installed on the relevant device, Telegram also provides an installation-free, official web interface. This can be used in any current web browser, but only cloud-based chats are possible here.

Sticker

As of May 19, 2015, users can create virtual sticker collections and publish them to friends. Since January 2016 it has also been possible to send individual MP4 videos without sound directly from the sticker panel. These act like gif animations . GIFs sent in Messenger are automatically converted into the much smaller MP4 format. Animated stickers have also been available since July 2019.

drafts

Unfinished messages in cloud-based chats and groups as drafts ( English Drafts ) is stored and synchronized between the user equipment. The draft remains in the edit area on each device until it is sent or removed.

Survey

From version 5.1 (December 2018) you can insert surveys in groups and channels without script programming, which the participants can answer. The number of votes cast and the percentage distribution of the answers to the up to ten questions that can be formulated in free text are shown in the chat after you have voted yourself. Since the version of January 23, 2020, multiple answers and a quiz mode are also possible, and you can choose whether or not the votes are to be cast anonymously.

Bots

Since June 24, 2015, Telegram has also been offering an extensive API to create your own bots . You can use various commands to control these in your own chat or in group chats. You can set whether bots in group chats have read rights to all messages or only to those that contain "@Botname". Many creative bots have emerged from the bot platform. There are special libraries to find these bots, for example the StoreBot, where users can rate bots and search for different categories. In January 2016, the bot platform was expanded to include so-called inline functions. Bots equipped with inline functions can then also perform functions in private chats or groups that do not contain them.

channels

On September 22, 2015 Telegram announced that "channels" ( English channels are) replace the previous distribution lists. These are chats in which only certain members (administrators) can write messages (visible to all members). In the case of these, it is not possible to determine who the author is, since the channel name is always specified as the sender. There are private channels and public channels. If channels are public, they have no subscriber limit. Anyone who has the link can join it. Only the number of participants is shown publicly, no names or phone numbers, and for each message the number of those who have read it.

Voice and video calls

Telegram introduced its own telephone calls at the end of March 2017. The calls are based on the end-to-end encryption of "secret chats" ( English Secret chats ). The connection is set up as peer-to-peer if possible, otherwise the Telegram server closest to the client is used. According to Telegram, there is a neural network that is working to learn various technical parameters about the call to ensure better quality of service for future applications. A secure, unambiguous voice connection can be verified by displaying the same emojis for the conversation partners. After a brief initial attempt in Western Europe, voice calls are now available in most countries. Video telephony between Android and iOS devices has also been possible since August 2020. You can start this from the profile page of one of your contacts or during the voice calls, everyone involved can switch their own cameras on and off.

Telescope (video news)

From version 4.0, which was published in May 2017, Telegram offers a dedicated video hosting platform called "Telescope". Videos can be up to a minute long, are shown in a round frame and are usually played automatically, an option that can also be deactivated. If they are sent in a public channel on Telegram, they will also be uploaded and published on telesco.pe. However, Telegram video messages and “Telescope” videos sent in private chats or groups will not be published.

Live locations

For fifteen minutes, one or eight hours, Telegram users have been able to share their location in the chat with version 4.4 since October 2017. If several users share their location in a group, they can be seen on an interactive map. The sharing of the location can be stopped at any time.

Social login

Since February 2018, Telegram users have been able to use a function for logging into third-party websites under the name “Telegram Login”. The gateway sends the Telegram name, the user name on the website and the profile picture of the user to the owner of the website, while a possible telephone number associated with the Telegram account remains hidden. The gateway is integrated into a bot that is linked to the developer's specific website domain.

safety

According to the encryption expert Rüdiger Weis , professor of computer science at the Beuth University of Applied Sciences in Berlin , Telegram used the SHA-1 hash function, which is now regarded as broken, up to MTProto version 2.0 . According to Telegram, this did not represent a security gap in the protocol used. The company also did not use the hash function in combination with a tried and tested standard encryption process, but instead used a technical solution it had developed.

Chat security

Telegram supports two types of chats:

Cloud based chats
This is the default setting. These chats are only encrypted via the MTProto protocol between the end device and the server. In addition, according to the operator, the data is stored encrypted on servers around the world. This is intended to ensure that states or secret services do not have access to the data even if individual servers are searched and confiscated. However, all data are always legible and permanently stored for the operator - and thus probably also for an attacker who gains access to the system. The security is roughly comparable to that of e-mail. Here, too, most providers encrypt the connection between client and server, but usually using the tried and tested Transport Layer Security protocol . Among others, Edward Snowden and the security expert and co-developer of the signal protocol Moxie Marlinspike criticized that the security of Telegram is based solely on trust in the operator. The MTProto protocol developed in-house is used for communication between the Telegram server and the end device. Its security and that of the overall concept as well as its marketing as a “secure messenger” have been criticized many times by experts.
Secret chats
These are not stored in the Telegram cloud and only transmitted end-to-end encrypted between the end devices of both chat participants . They can also be deleted from both terminals after a specified period of time (e.g. 30 seconds). This is to ensure increased security, since the plain text cannot be restored even if all servers are seized, as it is never saved on such a server.

Protocol and cryptography

Telegram uses the self-developed MTProto protocol. The developer of the signal encryption protocol Moxie Marlinspike and other cryptography experts criticize, among other things, the fact that Telegram's protocol uses cryptographic methods, but combines them with one another in an unproven way.

Since MTProto 2.0 Telegram has been using the SHA-256 algorithm as a cryptological hash function for both client-server and client-client (private) chats in order to determine the unauthorized manipulation of messages. In the previous version, the outdated SHA-1 was used, which had been criticized from various quarters as a critical weak point ( single point of failure ).

Since secret chats also need the server to forward messages, attackers who have access to the server can theoretically carry out man-in-the-middle attacks. To prevent this, Telegram offers users to authenticate each other. To do this, users compare a kind of fingerprint of their keys using an image.

Konstantin Kovshenin criticizes that the cryptographic keys are not generated entirely at random, as is common in cryptography, but are based in part on the message itself.

The sent messages are stored unencrypted in the memory of the device. If the device is taken into possession by an attacker or hacked remotely, these messages can be accessed.

Since the sole use of SMS messages is not a secure method of authenticating a user as legitimate, all messengers that rely solely on SMS can be attacked. It is possible for hackers (through a weak point in the SS7 cellular protocol) or government agencies (through access to the cellular network provider) to switch to the cellular network and thus intercept the authentication SMS. You can then use this to log into the messenger service. This is particularly critical with Telegram, as the entire “regular” chat history is on the server and can therefore be read by the attacker. Telegram has therefore been advising its users since 2015 to set a password in addition to the mobile phone number, which prevents this type of attack as long as the attacker does not also gain knowledge of the password. In 2016, state authorities in Iran and Germany succeeded in intercepting the authentication SMS for users who had not set an additional password, giving them access to the user accounts.

If the telephone number of a user is reassigned, the new owner unwillingly receives access to his Telegram account including all cloud chats. Unless the user keeps his phone number up to date via the app settings or has activated two-step confirmation, which is only optional.

A security analysis from May 2017 confirmed that Telegram had "serious and simple issues". There are problems with Diffie-Hellman key exchange and it was shown that the command line client can be used to find out when contacts are communicating with other contacts.

Problems with bots in group chats

In January 2019, security researchers demonstrated that group chats in which a bot is located can be tapped by outsiders. The group's (randomly generated) chat ID and the bot's API token are sufficient for this. This information can then be used to access the group's entire chat history. If a group insider passes this information on to third parties or if it is stolen from him, third parties can use it to monitor the group unnoticed.

However, ID and tokens can potentially also be accessed externally with great effort if attackers place themselves as man-in-the-middle and crack the TLS transport encryption.

Safety contest

In December 2013, an amount of US $ 100,000 was paid to a hacker who described a possible attack scenario.

On September 19, 2013, Telegram founder Pawel Durow announced that he would be awarding US $ 200,000 in bitcoin if the messenger's encryption was cracked. This hack competition launched by Telegram (see penetration test ) was criticized as an advertising campaign, since under the given restrictions, encryptions that were already completely broken would withstand an attack.

The contest was then repeated in November 2014, this time according to the clearance requested by security experts, so that hackers could act as fully-fledged clients or servers. In addition, the prize money was increased to USD 300,000. In February 2015 the competition ended without a winner.

privacy

The current versions of Android (from version 6.0) and iOS ask by default whether the user of an app would like to allow access to the address book.

The user can also permanently prevent synchronization with the Telegram servers within Telegram. The app also offers the option of deleting contacts that have already been synchronized on the server. Telegram performed better than WhatsApp , Blackberry Messenger and Line in the Stiftung Warentest quick test with a focus on data protection . Telegram transfers and stores all telephone numbers and also the contact names in the user's phone book and saves them permanently on the operator's servers, at least as long as they are available in the user's phone book. This means that Telegram only goes beyond the data usage of competing products with synchronized contacts, which transmit the telephone numbers or even just their hash values.

All communication content, with the exception of the secret chats, is stored permanently on the operator's servers so that it is legible - as long as all users involved in the conversation do not delete the respective messages or their user accounts.

The protocol makes it possible to determine the online status of a user at any time. It is not possible to turn this function off completely.

Messages are given a "read" status as soon as the user has opened them. In contrast to most competing products, this function cannot be switched off. The user can manually set the status back to "unread".

When registering, the user must enter his telephone number. According to the operator, this is necessary to protect the chats from bots and abuse. The user also receives a confirmation SMS message about this. Registration by entering an email address is not possible.

Telegram Passport security issues

With Telegram Passport, users can upload documents to the Telegram cloud through which their civil identity can be determined beyond doubt. The background to this is that when a Telegram cryptocurrency is introduced in the future, there will be legal requirements for identifying users, similar to the way in which ID data must be presented to open a bank account.

Telegram has developed its own end-to-end encryption for this, in which the user documents, such as scans of ID cards or driver's license, are encrypted by the user and are only uploaded to the cloud after encryption. The user can then decide for himself whether and for which third party to decrypt the data.

Technically, an intermediate key is generated for this from a password set by the user. The actual crypto key for data encryption is then generated by a random generator. The actual crypto key is then encrypted with the intermediate key. The crypto key can then be uploaded to the Telegram cloud without the operator being able to use it to decrypt user documents, since the crypto key is encrypted with the intermediate key.

However, security experts warn that the encryption implementation designed by Telegram provides several vulnerabilities:

  • SHA-512 is used to derive the intermediate key. With a little technical effort, however, all possible passwords can be tried using brute force in order to obtain the intermediate key.
  • When verifying the actual crypto key, a simple modulo calculation is used, which an attacker can make use of to try out keys more quickly, since he simply discards all values ​​that do not correspond to the modulo value.

Unwanted content

Telegram's guidelines state that only publicly accessible content, i.e. public channels, groups, stickers or bots, can be blocked if it violates the law or copyright.

On November 18, 2015, Telegram announced on its own channel that it had blocked 78 channels related to the so-called Islamic State . In addition, a better way will be provided in the future to report such public content in Telegram. However, the app is still used by supporters of the terrorist organization. On December 26, 2016, Telegram opened a new official channel called @ISISwatch on its own platform, in which it was announced that around 2000 accounts that can be attributed to IS are blocked per month.

Licensing

Most of the official clients for Telegram are open source free software . Adapted versions ("unofficial versions") must also provide the source code. Telegram's server-side infrastructure is proprietary . A review of many operator information, such as the security of the cloud chats and other data stored on the servers, such as contacts, is therefore not possible.

See also

Web links

Individual evidence

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