WhatsApp Alternatives: Telegram vs Signal - Which offers the Best Privacy?

When WhatsApp updated their Privacy Policy on January 6, 2021, users of their service went into a frenzy when they were asked to share their data with other Meta companies, which includes Facebook, WhatsApp, and Instagram.  

Previously believed to be secure, WhatsApp lost the trust of its users who began looking for alternate private chat options.   

According to Statista.com, as of January 2021, WhatsApp was the most utilized chat app in the world, with approximately 2 Billion users, followed by Facebook Messenger and WeChat with 1.3 and 1.213 Billion users respectively.  Then in the 4th and 5th spots were Telegram and Signal each with 500 Million users. 

The rise of Telegram and Signal.

In early 2021 after the WhatsApp privacy update, WhatsApp users began flocking to other chat apps in search of a more secure option.  The two that have received the most acclaim were Telegram and Signal. 

Telegram vs Signal from a Private Investigator’s Perspective

Being a Private Investigator, my go-to chat app for privacy and security for years has been Telegram.  But I recently started using Signal and have had an equally great experience.  

Both apps have key differences and features that everyone must know.  Below I will go into detail about the differences:   

First, I will start with Telegram…

Telegram Background:

Telegram is a for-profit app that was launched on August 14, 2013 by brothers Pavel and Nikoali Durov.  Originally developed in Russia, the brothers left the country due to IT regulations and have relocated to different jurisdictions around the world.  As of the writing of this article, they reside in Dubai along with the rest of the Telegram team.    

Telegram is a free app and claims to use an open platform (although it is not believed to be fully open source).  Back in December 2020, Pavel Durov announced plans to begin using an Ad Platform in public one-to-many channels and also premium stickers as monetizing strategies in 2021.  Telegram is available for smart phones, tablets, and desktop platforms.

Telegram Privacy:

Telegram uses server-client encryption in private, group, and one-to-many chats, called Cloud Chats.  This means data from these chats are stored on the Telegram encrypted cloud servers.  Although this type of encryption generally protects data against external threats, it is still vulnerable to insider attacks (for example, a rogue Telegram employee accessing the server … like Snowden did with the NSA).  

Here is a visual description of how the Cloud Chat data is processed by Telegram:  

As you can see, Telegram Cloud Chat is not the preferred choice for complete privacy in a chat app and as such, has come under scrutiny by tech/privacy experts.  

But don’t write off Telegram just yet … let’s talk about their Secret Chat.

Telegram’s Secret Chat is protected by client-client (also known as end-to-end) encryption.  The Secret Chat data is not stored on Telegram’s servers and is only store on the user’s device where the app is installed.  Simply put, Telegram routes the encrypted data between Secret Chat recipients and does not store the data on their servers.  No internal/external hacker will be able to see the unencrypted data as it passes through the Telegram server.  

Here is a visual description how the data is processed by Telegram when using Secret Chat:

*Chat data is routed across the Telegram network but not saved on the servers.  

Let’s do a deep dive into the privacy features of Telegram’s Secret Chat.   

What if someone gains access to a mobile phone that is hosting the Secret Chat? 

If someone accesses a mobile phone (say a spouse who knows the device’s passcode), they could potentially access Telegram’s Secret Chat.  But Telegram has safety features that can prevent this type of unauthorized access but they MUST be enabled in the app.

These include: passcode protection, two-factor authorization, fingerprint scanning, and no message prompting with the subject text unless you are actively logged into the app.   

What are the in-chat privacy features that Secret Chat offers between users?

While in a Secret Chat, chat room members will be notified when screenshots are captured, messages can be self-destructed, and a ‘delete for everyone’ option is available.  Telegram also offers complete anonymity which will be discussed below.   

How do I make myself completely anonymous on Telegram?

To be anonymous on Telegram means to have a Secret Chat where your chat partner does not see the phone number associated with your account.  For a Private Investigator this could be useful when obtaining information from a source where their phone number is known but the investigator wishes their contact information remain hidden.  

To initiate this feature, navigate to Telegram’s Settings > Privacy Settings > Phone Number.  

It will then ask: Who can see my phone number? 

Nobody must be selected.

BUT there is a catch!

The phone number of the person would like to chat with anonymously cannot be saved on your device (SIM Card) as a contact. You will be required to add the person as a contact in Telegram (ONLY) … but do not save their phone number on your actual device. If the person you are adding to the Secret chat room is saved as a contact on your device (on your SIM), they will still be able to see your phone number even if you select Nobody can see your phone number.  Therefore, to remain anonymous, do not save the recipient’s phone number as a contact on your device.

Final thoughts on Telegram from a Private Investigator’s perspective: 

Telegram’s default private, group, and one-to-many chats lack privacy and appear to be susceptible to internal threats from within Telegram.  But the Secret Chat, on the other hand, is an end-to-end encrypted chat option with the ability for users to be completely anonymous in addition to other chat privacy features.  

Now, let’s look at Signal…

Signal Background:

Signal is the successor of the RedPhone encrypted voice calling app and the TextSecure encrypted texting program.  These programs were launched in 2010 by Whisper Systems, which was co-founded by Moxie Marlinspike and Stuart Anderson.  In 2011, Whisper Systems was acquired by Twitter.  

About 2 years later, Moxie Marlinspike left Twitter and launched Open Whisper systems which developed an open-source encrypted chat protocol now known as Signal Messenger.  The Signal Technology Foundation, a non-profit organization, currently supports the Signal App. 

Signal Messenger is a fully open-source project that offers end-to-end encryption.  The source code is available on GitHub and is open to the public. 

Signal’s Privacy:

Right out of the box, Signal is a great day-to-day app for those concerned about privacy.  All Signal chats by default are end-to-end encrypted and messages are stored on the phone’s of the users, not the servers.  No messages are permanently stored on the Signal servers.   The only time messages are stored on the servers is when the message is waiting in queue to be delivered (for example, if a message recipient’s phone is turned off, the messages will wait on the servers until the phone is turned on and messages delivered.)  But since the data is encrypted before the data reaches Signal’s server, the unencrypted data will not be intercepted while in queue.

Below is visual description of how data is processed across the Signal protocol.  

*Chat data is routed across the Signal network but not saved on the servers.  

The above visual is nearly identical to the Telegram Secret Chat description provided earlier in this article.  

What are in-chat security features of Signal Messenger?

In addition to end-to-end encryption, Signal offers no screenshots, messages can be set to self-destruct, and a ‘delete for everyone’ option is also available.  

Can you remain completely anonymous on Signal just like Telegram’s Secret Chat?

No.  Signal is connected to your mobile phone number.  So even though you have the option to change your Signal Profile name, the app is connect to your phone number. When you initiate a chat, your phone number will be visible to the other members of the chat.

Final thoughts on Signal from a Private Investigator’s perspective: 

Signal is a great day-to-day chat option for Investigators to converse with team members and clients alike.  But the lack of anonymity limits Signal’s use in high-profile and sensitive scenario’s where the Investigator must remain anonymous over the chat.   

The big debate, Telegram vs. Signal:

As a Private Investigator and President of an Investigation Agency who takes privacy seriously, I recommend use of both Telegram and Signal depending on the situation.  

For day-to-day operations including correspondence between team members, groups, and clients, Signal is the best option because of the default end-to-end encryption and due to the fact that chat data is not stored on Signal servers.  

But for sensitive and high-profile investigations where complete anonymity is required, Telegram’s Secret Chat offers two level of encryption (end-to-end and client-server) and is the best option for anyone who wants to chat anonymously and securely.