Signal Messenger App: Tips on Making a Solution for Secure Communication
Communication changed once and for all when people started using gadgets and applications to make calls and exchange text messages. However, there are certain drawbacks like privacy and data security. This is why secure messaging apps are becoming more popular.
If you have ever wondered how to create an application like Signal messenger, this article is exactly what you should read to understand.
Magic Behind Signal App
So, what makes Signal messenger unique, how does Signal work, and why is it considered a precursor to the most secure free messaging apps on the market?
Let’s find out!
What is Signal App and How Does it Work
The Signal messenger was built on the basis of the existing RedPhone and TextSecure applications and was launched in March 2015 by Open Whisper Systems.
Also, Signal source code is available on GitHub for anyone who wants to examine it or check for security flaws.
Aside from that, their repository is set up with BitHub so that highly-experienced developers can easily configure and deploy Signal and make money from it if their pull request is accepted.
Signal allows for encrypted calls to be made from anywhere in the world; the same goes for Signal text messages.
Is Signal App Really Secure?
The Signal app uses end-to-end encryption, as it means that all messages are encrypted before they are sent and can only be decrypted on the device of the intended recipient. The only way to read the message is on the sender’s or recipient’s device.
The Signal messenger app relies on the following cryptographic protocols:
- Extended Triple Diffie-Hellman (X3DH)
- Double Ratchet algorithm, Curve25519
- AES-256
- HMAC-SHA256
What exactly does it mean to be secure?
According to the Electronic Frontier Foundation (EFF), there are seven criteria to assess how secure a chat app is, namely:
- communication encrypted in transit
- no provider has access to the key the communication is encrypted with
- independent verification of a correspondent’s identity
- secure past communications if the keys are stolen
- code open to independent review
- well-documented cryptographic design
- an independent security audit
Signal messenger conforms to all the standards. Below you can see the security assessment of the Signal in comparison to other chat apps:
Signal Messager: Features to Include
The core feature of the Signal messenger is encrypted messaging, but it certainly has more functions that are worth mentioning, like:
- Registration with a phone number
- Disappearing messages
- Voice and video calls
- Group chats
- Content sharing and entertainment
- Platform-specific features
- Security and encryption
Implementing security protocols is not an easy task, rather, it requires a huge amount of effort. One of them, for example, is using Telegram API (another secure chat app). This has its drawbacks as well; you do not have access to, or control over, the database.
Relying strongly on third- party security is a questionable decision. Your provider can change something in their terms of use and you won’t be able to do anything with it or influence it. And it can happen so fast that you will have no time to switch to anything else or create your own implementation of storing and transferring messages on back end.
Also, no matter how secure a protocol is, technologies are evolving very fast and hackers are also honing their skills. The things that were secure before can be compromised in a few years. Just like it happened with RSA cryptographic algorithm. So, someday even the best encrypted messaging app might be corrupted and user sensitive data may come to the wrong hands.
Igor Vlasenko, Team Leader, Senior Back-end Developer
Signal App Development: Minimum Budget Required
So how much does it cost to develop a solution like the Signal?
The price and timeline will greatly depend on the features your messenger will ultimately have, their complexity, the application design, and the vendor you hire.
At MLSDev, the whole process of software development is divided between the discovery and development stages. The image below shows this in more detail.
Let’s use the most basic features that every chat app should have to calculate a minimum required budget for a solution like the Signal. They include the following:
Registration
- Login with a phone number
- Phone number confirmation
Contacts
- Access to all contacts
- Segmentation of contacts into those that have and do not have the messenger installed
Invitations and sharing
- Ability to invite friends or spread the word using the native sharing function
Chat
- One-to-one instant message exchange
- Message statuses (read, unread)
- Edit or delete messages
- Send pictures from the gallery or camera
- Push notifications
Additional Features
- Voice messages
- Stickers
If we add up all the services that are included in our process and the time required for the development of the above features, the first version of your product will cost you not less than $30–50K (discovery and development stages combined).
However, when you move to the next versions of your application, features will add up and increase the overall app development cost. Don’t expect the price for further versions of your app (for iOS or Android) to be less than $100K.
Please note that our estimations are very rough and that the final cost of app development may be extremely different.
Is Building the Next Messenger Worthwhile?
There are some strong competitors like Telegram, WhatsApp, Google Allo, and Facebook Messenger, just to name a few. So, despite possessing the same core functionality, each of these apps has its own tweaks and unique features that make them lighthouses in the endless ocean of applications.
If you feel that your app idea can bring value to users and meet their needs, it is definitely worth giving it a try.
This is a summary of an article published on MLSDev blog. If you would like to learn a detailed description and additional functionality of the Signal app— read the full article.
