Many of us need a secure means to communicate for work and socialising. Uses can include making voice calls, sending text messages or sharing images. Knowing that the content messages will remain private and not subject to misuse can be important for many reasons.
Coincidentally, many of us use social networking services to broadcast to the world or see what others are doing. We accept that the price for this convenience is sharing data that can profile us for targeted advertising.
The problem comes when these two separate services overlap. For example, secure messaging services and social networking services should ideally not be sharing information. The acquisition of WhatsApp’s popular messaging service by the social networking service Facebook is a case in point. The data sharing between WhatsApp and its parent Facebook (now confusingly Meta) announced at the start of 2021 has seen WhatsApp users looking for alternatives.
This article will look closely at the two leading alternative secure messaging services, Signal vs Telegram. The goal is to allow you to make informed decisions about the best alternative to WhatsApp for you.
Signal started life in 2014 as the first free iOS app for end-to-end encrypted voice calls. The US-based not-for-profit Open Whisper Systems now manages the service, formed by the original creators of the app. It’s a reliable and stable platform with total transparency, thanks to its open-source approach.
The only significant issues came in January 2021, following the WhatsApp policy change announcement, when a surge of new users temporarily overwhelmed the company’s systems. Around 7.5 million users joined in a single week during this period.
Telegram started life a year earlier in Russia in 2013 when the Telegram messenger service began. Since its creation, it has relocated several times to Berlin, London, Singapore and now has a Dubai base. Each move was in response to changes to governing regulations in each country. Officially its registration is as a US business entity, but it has no official offices.
Telegram has also recently expanded its user base, reporting that around 25 million new users joined over three days during January 2021.
Telegram has published some of its services as open-source, but the server-based centralised control software is closed-source and proprietary. This lack of transparency prevents independent scrutiny of the robustness of implemented security.
For simple messaging, there’s not much to choose from for Signal vs Telegram. Both can share audio messages, images, videos, files, contacts and location information with individuals or groups. The critical difference is that Signal protects all messages using encryption, while Telegram only protects messages that use a special “secret chat” option.
Signal stores the messages on the sender and recipient devices. However, there are options for message mirroring using a Chrome browser extension to have an alternate access method from any device that supports the Chrome browser.
Signal also has the facility to backup messages to a secure cloud service, and there’s an archive option to keep chat lists manageable.
By default, Telegram stores its unencrypted messages on a central server managed by the service provider. Consequently, users with multiple devices can access all their unencrypted messages from any device, even using website access. However, a Telegram user must stick to a single device to access the protected “secret chat” messages.
Signal allows voice and video calls to up to five recipients, while Telegram will enable calls to large groups.
Signal limits group chats to 1,000 users, while Telegram allows a massive 200,000 users.
Telegram includes a channel feature for broadcasting messaging to recipients who can receive but not reply to the messages. The audience of this channel messaging can be open to the public or limited to invited group members.
Signal limits the transfer of files to a maximum size of 100 megabytes, while Telegram allows two gigabytes.
File storage for Signal users depends on the free memory available on their device. For Telegram users, the service stores files on the central servers, which currently offer unlimited storage for an indefinite period.
Telegram supports using bots to automate conversations, though at the expense of reduced privacy protection for users. In contrast, Signal does not allow the use of bots. This is a critical distinguishing factor for businesses looking for a bot-based messaging service when looking at Telegram vs WhatsApp or Signal.
Users can enable Signal to be the default app for all text messaging, while this feature is not available to Telegram users. However, one point to note is if you use Signal to manage all SMS messages on the device, other messaging apps will no longer have access.
Message Privacy Protection
The principal reason for using an application such as WhatsApp, Signal or Telegram is message privacy. Here Signal has the advantage.
Signal implements complete end-to-end encryptions and offers the self-destruct option for all messages. These options apply to both messaging individuals and groups. In contrast, Telegram only offers these critical features for “secret chat” messages with individuals.
But what do these terms mean? Let’s look in more detail.
Encryption is a method of securely scrambling (encrypting) data so that anyone who does not have the key to unscramble (decrypt) the message will not understand it. There are various mathematical-based techniques to perform the encryption and decryption actions. The security of the message depends on several factors:
- The robustness of the encryption/decryption algorithm prevents anyone without the key from cracking the code and reading the message;
- The complexity of the key prevents anyone either guessing the key or using the brute force approach of trying every possible key to find the correct one;
- The integrity of the mechanism for sharing keys between the sender and recipients prevents anyone else from stealing the key.
No encryption is perfect, and researchers often find flaws in algorithms that make cracking codes possible. Computers are getting more powerful, allowing them to try more keys in a reasonable period. However, using one of the latest algorithms with a sufficiently long key length makes the chances of cracking the code by the world’s best supercomputers remote enough to be secure.
End-to-end encryption means that the sender’s device encrypts the message and the recipient’s device decrypts it. It does not matter what route the message takes between the two devices or if copies sit in temporary locations along the way. The encryption protects the message content between the two devices.
In contrast, some secure messaging systems use encryption but not end-to-end encryption. For example, some service providers pass the message in plain text from the sender’s device to their computer systems. Only then do they encrypt the message and send it to the recipient. Anyone hacking the messaging service provider or a rogue employee could see the original message in this example.
Signal uses its own Signal Protocol developed by Open Whisper Systems in 2013. The algorithm is available as open-source code, meaning it is free for everyone to use. More importantly, anyone can see its implementation and check for weaknesses. Incidentally, WhatsApp uses this encryption protocol.
The protocol also hides the sender’s identity from the systems the message transits. Thus, anyone monitoring the flow of encrypted messages can see where the messages are going but not where their source is.
Telegram uses its own MTProto protocol, the release of this latest version being in 2017. The previous iteration of this protocol contained significant flaws that offered poor levels of security, but this latest version is significantly more robust. However, it is still less secure than the Signal Protocol.
A crucial feature of the Signal Protocol is forward secrecy, meaning that even after the compromise of an encryption key, the confidentiality of future messages is still safe. The most common method for attackers to steal keys is to install malware onto the sender’s device. Therefore, anyone stealing a key will have access to old messages but no new messages.
Simply speaking, a self-destructing message will automatically delete from the senders’ device after a configurable period after sending the message. Alternatively, the message may automatically delete from recipients’ devices a configurable period after reading the message.
The advantage of using the self-destruct option is that no old messages will remain in memory where the person stealing or finding the device could access them if a user loses their device.
Self-destruct for recipients does have its limitations; after receiving a massage, it’s straightforward for the recipient to copy the message or forward it with self-destruct disabled.
A key consideration with any messaging service is what information the service provider collects and shares. Unfortunately, this is where WhatsApp came unstuck.
- Signal collects and holds the phone number for the device accessing the messages;
- Telegram collects and stores the phone number, along with the contacts and the device’s IP address.
These compare favourably with WhatsApp’s collection of detailed device information and behavioural data, including location tracking, purchasing information, payment details, and other details helpful in creating detailed user profiling for advertisers.
Signal also has built-in features to help protect user privacy. An incognito keyboard option prevents message content from ending up in a local dictionary on the sender’s device. A sealed message option hides the sender’s device details from a recipient, such as their IP address.
Signal offers absolute privacy, while for Telegram, this is more limited. Telegram privacy is less rigorous as their servers hold copies of all unencrypted messages and a copy of the address book of every user. Telegram also collect details of IP address, recipients and the time stamp for each message. In contrast, Signal only collects and stores the date of the last connection to its service. In the comparison of Signal vs WhatsApp, this difference is enormous.
This limited personal data collection is essential due to the US location of the Signal service. Here, government and law enforcement agencies can request user data under rules that prohibit the service from informing users of the request.
Telegram attempts to make access to secret chats information harder by storing the encryption keys in a different geographic location to the message data. The result is that access to these encrypted messages requires the cooperation of governmental or law enforcement agencies in the two different jurisdictions.
Both Signal and Telegram support the most popular platforms, including Windows, Linux, macOS, iOS, and Android. Both also use a Chrome browser extension for web-based access.
Telegram also supports Windows Phones and has a website access portal for universal access to the unencrypted messages stored on its servers.
It’s important to note that Telegram’s “secret chat” option is only available using its mobile apps and so is not available when using a desktop client or the web-browser access.
One significant difference is that the Signal service is dependent on Google services for notifications. In practice, this only affects devices with custom Android operating systems.
Both Signal and Telegram are simple to install, and anonymous configuration of accounts is possible if necessary.
Telegram has more options to configure the user experience, such as themes and colours, though Signal also has similar but more basic options. This simplicity makes Signal easier to set up and use.
Telegram is more focused on social media messaging and broadcasting as opposed to Signal’s secure messaging.
Telegram supports sending uncompressed images, a key factor and what makes Telegram better than WhatsApp and Signal for sharing photos. However, Signal does have a useful built-in face-blur feature for use when messaging photographs.
An important consideration is Signal aims for a global audience, bypassing censorship controls by using a proxy server connection option wherever the service is geographically blocked.
Both services operate on a non-commercial basis, so support relies on online help and volunteers to address specific issues.
Notably, Telegram does not support visually impaired users, while Signal has the distinction of currently being the only app that offers blind users a secure messaging service.
The answer to the question of Signal vs Telegram may come down to whether you value privacy over functionality. If privacy is the critical factor, then Signal has overwhelming advantages over Telegram.
Still, the primary influence will be what application your contacts use. It may be hard to persuade your friends and family to switch to a different app if they use an alternative. However, the significant differences between the options may well be enough to persuade them.