Signal is by far the best when it comes to protecting user privacy. It is better than Whatsapp by a long shot. Signal uses the open-source Signal Protcol to implement the end-to-end encryption in its messages.

Signal encrypts your messages, calls, and even the metadata. Signal is the only messaging app that encrypts even the metadata to protect the user from all fronts.

Metadata refers to the data about the data. For example if you share an image, it contains the EXIF information about the device model, camera resolution, time, location, etc.

Signal uses state-of-the-art end-to-end encryption (powered by the open source Signal Protocol) which is touted as the gold standard of encryption by many cybersecurity professionals. Even Signal can't read your messages as the chats are end-to-end encrypted.

End-to-End chats are encrypted from the sender's device and decrypted at the reciever's device using a secure cryptographic key. And since the messages are stored on the local storage instead of the server, only you are in control.

To prevent physical access to the messages, the messages are stored on the storage in encrypted format. Therefore if your mobile is stolen or the storage is compromised, the chats are irretrieveable. Moreover, the app supports biometric authentication/screen lock to prevent unauthorised access.

Signal stores as minimal data as possible. If ever the signal servers are hacked, they will only contain the account creation date and last connection date. See how even FBI lost it to the privacy of Signal messenger here.

"The only Signal user data we have, and the only data the US government obtained as a result, was the date of last use -- NOT user messages, groups, contacts, profile information, or anything else." -Signal.org

Signal doesn't directly sends any of your contact list to the server. Instead, it uses a cryptographic hash function to obfuscate phone numbers before sending them to the server.

As with text messages, Signal includes a clever method for confirming the person you're calling is who they say they are and not intercepting your call. Both callers see the same randomly generated two-word phrase.
If you think you might be speaking to an imposter, simply demand the other caller say the security phrase.

In addition to the end-to-end encryption that protects every Signal message, The Signal service is designed to minimise the data that is retained about signal users. By design it does not store a record of your contacts, social graph, conversation list, profile name, avatar, group memberships, group titles, etc.

Being open source is another perk of Signal messenger, as the whole code is published on github, anyone can verify the code, suggest improvements, report security errors. In Contrast, whatsapp is closed source, so any vulnerability has a high chance of being expoloited.

Ok, now you have an idea about the security of signal messenger. Let's talk features.

Signal has all features that Whatsapp has to provide (excluding status). Every feature works seamlessly within the app. Moreover, there are many unique features that Whatsapp hasn't added yet. So, take a look at some unique features.

Ever wanted to jot down something quickly? Why not use Signal for that too. Compose a message and select "Note to Self" in the contact list. Don't worry this is end-to-end encrypted too. You can even write your passwords here (although i would recommend a password manager for that).

Want to send your photo, but don't want it to be stored on the reciever's device? Don't worry, Signal has you covered. Just select to send a view-once message and it will be deleted as soon as the reciever views the media. kaboom!

Fed up as Whatsapp compressed the images, and the reciever got a fuzzy image? Not here, signal transfers the media files as-it-is and doesn't perform any compression algorithm. So, images will be as clear as they are in your phone.

Want to blur some part of an image before sharing? No need for a separate app. Signal has the option in the app itself. You can also blur faces you don't want to reveal.

Signal can also be used in place of the traditional SMS app, this allows you to encrypt the SMS on the device too.

While using the app, the keyboard won't record your typing styles and word personalisation. However I would recommend using a secure keyboard app altogether.

You can backup chats locally, but the chats are encrypted using the pin you set during registration. This backup can even be uploaded to the cloud or migrated to the SD card.

You can react to the messages, same as you can react to comments on facebook.

Signal supports all major platforms (Android, iOS, MacOS, Linux, Windows). Each signal app runs it's own independant instance with android app being the master.
Essentially this means that, you can use signal from your desktop too. But the phone doesn't need to be online for you to use signal. But in case of whatsapp the phone need to be online for the client to work.

"I use Signal every day."

Edward Snowden
Whistleblower and privacy advocate

"I trust Signal because it’s well built, but more importantly, because of how it’s built: open source, peer reviewed, and funded entirely by grants and donations. A refreshing model for how critical services should be built."

Jack Dorsey
CEO of Twitter and Square

"I am regularly impressed with the thought and care put into both the security and the usability of this app. It's my first choice for an encrypted conversation."

Bruce Schneier
Internationally renowned security technologist

Whatsapp isn't half as secure as Signal, it has many security threats. In the race to provide a convenient experience, whatsapp has traded off privacy with a great margin.

The chats are not encrypted while in the storage, also, it is kept in google drive/icloud in plain text format without any encryption.

Yes, what about the fact that whatsapp has already been compromised by an Israeli firm, which installed spyware on top of whatsapp and intercepted all the chats. This spyware was found in about 1400 high profile government officials using Whatapp. The israeli firm was able to bypass the end-to-end encryption and read all messages. Read more about it here.

Apparently whatsapp uses the same encryption protocol for sending/receiving messages as Signal, but it has modified the open source code and installed a back door in it. This backdoor helps whatsapp to easily bypass the end-to-end encryption and get access to all your chats and information. Read more about the exploit here.

First of all, the encryption standard is open source, and signal doesn't tamper with the break-free code. But since whatsapp is closed source so nobody can see what facebook is coding behind closed doors. Maybe they weakened the encryption, added a tracker/spyware, who knows and facebook isn't trustworthy afterall.

Well, you seem like a tough nut to crack.

Before explaining further i want to ask you something.

This is perhaps the most compelling reason to use Signal. As whatsapp is owned by Facebook, and Facebook is known for it's long-standing lack of respect for user's privacy.
Facebook isn't secure when it comes to data collection and handling, from the Cambridge Analytica affair to it's practice for sharing data about users with phone manufacturers.

In 2017, European regulators took action against Facebook for sharing Whatsapp's users' phone numbers with its Facebook social network for advertising purposes. Firmly in breach of data protection regulations. Facebook had previously claimed it would never implement such system.

Facebook's lack of concern for users' privacy is the reason why Whatsapp co-developer Brian Acton left Facebook in 2017 and co-founded Signal Foundation with Marlinspike later. Brian has harshly criticised Facebook's approach to privacy and revealed that Facebook coached him "to explain that it would be really difficult to merge the data of Facebook and Whatsapp together" when giving statement to European Union regulators in 2014.

Facebook's desire to insert adverts and commercial messaging into Whatsapp and potentially compromising it's security prompted Acton to leave Facebook, and sacrificing about $850 million in stocks in process. Acton's fellow developer also walked out on Facebook following reported disputes with the company over its efforts to weaken encryption.

Facebook is also thinking of merging whatsapp with Facebook keeping in mind the large volume of whatsapp users that aren't on facebook.

That isn't true, humans need privacy, it is just that you don't understand the value of online privacy. You have curtains at your home right, may i ask why? Because you don't want random stanger to look at your personal activities (eating, watching tv, etc). Having curtains doesn't mean the person is cooking meth inside the house. It means you are concerned about your privacy.
Same stands for online privacy, you don't need to be a drug seller to care about your privacy. Privacy should be for everyone. But people generally misinterpret it.
Tech giants such as Google and Facebook are providing majority of their services for free, still they generate billions in revenue. Where does the money come from? It is from your data, the data that is sold openly to the highest bidder. This data is then used to uniquely identify you and then track your habits across websites and present your with targeted ads.

Frankly I am ok with it too, as it helps to generate revenue but the problem arises when the ads are targeted. Normal ads are just related to your search query. But targeted ads are sent by analysing the usage pattern, behaviour, and multiple other factor which is a huge breach of trust. Targeted ads help the company to extract maximum benefit from your valuable data.

Well the short answer would be yes. But there are multiple factors at play here, google secures your data from external threats, but it doesn't stop them from misusing it themselves. As in the case of an ad company purchased by google, that tracks the users and points them targeted ads, this ad company has access to the google servers and has records of the users which is misused by google.
Also, since all google services are closed source and tightly integrated with android (preinstalled google apps) if they want they can compromise majority devices with just a software update. Code of closed source software can't be viewed so companies can easily bake in spyware that can export behavorial data to its servers.

Still not convinced? Read the articles about google from some of the reputed websites.
cnet
tech crunch
Guardian

Well tell them to switch too, it doesn't cost anything. You just have to download a free app. Signal features provide above and beyond whatsapp. Also, someone has take initiative and start the change, tell your friends to incorporate it slowly and build and ecosystem in which you are using whatsapp less. Don't push it, slowly try to shift towards signal and don't uninstall Whatsapp on day 1.

Ok, then how about keeping both the apps, and using signal wherever possible. Even if you are not using signal's encrypted messaging services, it can work as an SMS app hence it will serve a purpose no matter what. We need to work together to break this monopoly of tech giants. We need to support OPEN-SOURCE software which is free of cost and protects your privacy and installing signal could be a great start. Kindly consider.

Further improvement/pull requests are most welcome, I'll be waiting. Contact me here -