Not WhatsApp: Which Applications Truly Protect Business Secrets

If your company still officially uses email as the main means of communication, while unofficially everything goes through applications like WhatsApp or Viber, then you have a problem, both in terms of security and regulation. Most popular chat applications were created as toys for consumers, not as tools for protecting business secrets, negotiations, due diligence materials, or internal crises.

The non-profit project Privacy Guides, which focuses exclusively on privacy protection and has no commercial interests, has published an updated overview of the ‘best private instant messengers‘. The focus of these applications is clear: protection against passive attacks, mass surveillance, and surveillance capitalism, i.e., a model in which companies thrive on analyzing your communication traces.

For business users, the message is simple: it’s time for a secure messaging strategy, not a random choice of the application ‘everyone uses.’ According to Privacy Guides’ analysis, we are witnessing a quiet but massive migration of professionals from commercial platforms to tools that offer a ‘Zero-Trust’ architecture because it is no longer a question of ‘do you have something to hide,’ but ‘do you have something to protect.’

Tools that Redefine Security

Privacy Guides does not create another ‘top 10’ clickable list. They set strict, pre-defined criteria and then check who truly meets them. For an application to make this list, it had to meet certain standards. This means that every application must have open-source clients (the code is public and can be verified), end-to-end encryption (E2EE) that must be enabled by default for private messages, must support forward secrecy, frequent key rotation so that the compromise of one key does not unlock the old archive of messages, and must have an independent third-party security audit. Additionally, the application must not require sharing identifiers such as phone numbers or emails with contacts unless the user wishes to do so.

For business, this practically means that if you use a tool that does not meet these criteria, you have de facto decided that sensitive internal communication is not fully protected.

Signal: The Gold Standard for Most Users

The first recommendation on the list is expected, and it is the application Signal, which is also the most well-known application on this list. It is a free application developed by the non-profit organization Signal Messenger LLC and uses the Signal protocol, which is practically the industry standard for secure messaging today. Signal has become the de facto standard for serious business communication from a whistleblower application. Why? Because of the balance between usability and the Signal protocol, which is considered the most secure on the market.

For managers, the key feature is Forward Secrecy. This means that even if an attacker steals the decryption key today, they will not be able to read your messages from yesterday. Keys are constantly rotated, and the game-changing novelty is the hiding of phone numbers. Signal now allows the use of usernames, meaning that employees can communicate with clients without sharing their private mobile numbers, thus creating a clear boundary between private and business identity.

An important point for business users is also the minimization of metadata. In the background, Signal hides metadata as much as possible. Groups are designed so that the server does not know who is in which group or what they are called, and part of the sender’s identity is also hidden (sealed sender). In other words, the service provider sees minimal information. For management and IT departments, Signal is today the best compromise between usability and security: sufficiently ‘tame’ for the average employee to accept, yet robust enough to pass serious security and compliance analysis.

Molly: A Fortress for Android Users

If Signal is the standard, Molly is its armored version intended for high-risk sectors such as finance, law, or investigative journalism. It is a fork of Signal for Android that brings military-grade security features. Molly addresses the problem of physical device theft as the database on the mobile phone is encrypted, and data can be automatically deleted from RAM. For managers traveling to regions with a high risk of industrial espionage or device seizure at borders, Molly offers the option to route traffic through the Tor network, making the user’s location invisible. For a typical corporation, Signal is quite sufficient, while Molly makes sense for narrowly defined groups, such as security teams, investigative journalists in the company, law firms, and anyone professionally engaged in highly sensitive communication.

SimpleX and Briar: Tools for ‘Red Zones’

The third and fourth recommendations are more specialized tools, but for certain industries and situations, they can be crucial. When it comes to sensitive acquisitions or confidential negotiations, metadata is your biggest enemy. This is where SimpleX comes into play. SimpleX offers identity-free communication. This means that this is the first messenger that has no identifiers, no phone numbers, no emails, not even fixed usernames. It operates on a decentralized network, and contacts are established by scanning a QR code live, which eliminates Man-in-the-Middle attacks.

For the business world, SimpleX offers quantum resistance and a ‘unidirectional queues architecture’ that prevents user profiling. If you do not want anyone to know that your company is negotiating with a competitor, SimpleX is the tool of choice. This tool is most often used by organizations operating in authoritarian regimes, investigative journalists, lawyers, and companies that want to separate a certain part of communication from any classical identity infrastructure.

Briar: No Internet, No Problem

Briar is designed for scenarios where the internet is unstable, censored, or completely blocked. By default, clients communicate over the Tor network, making censorship and surveillance difficult. If there is no internet, Briar switches to a local network via Wi-Fi or Bluetooth, creating a kind of mesh network, so messages travel from device to device until they reach the recipient. Adding contacts is not trivial as both parties must manually add each other via a briar:// link or by scanning a QR code.

Briar is not a tool for everyday internal chat culture in a corporation, but it can be part of a crisis plan, for example, for crisis teams, field teams in disaster areas, or for organizations that must have a communication plan in case of targeted blockades.

Security is an Investment, Not an Expense

Privacy Guides sets clear criteria for modern tools. They must be open-source (the code must be verifiable), have E2EE (end-to-end encryption as the default setting), and be independently audited. For modern companies, transitioning to these tools is not paranoia, but strategic hygiene. In an age when data leaks in all directions, using tools that do not collect data is the only way to ensure that they will not be compromised.

The Shadow of ‘Chat Control’ and the Future of Business Secrets

Communication applications have become critical business infrastructure. Chat is no longer an ‘incidental channel’ for arranging coffee, but a digital space where real negotiations take place, decisions are made, and documents are exchanged. That is why relying on SMS (which is not encrypted) or commercial applications whose business model depends on monetizing your metadata becomes an indefensible risk.

For most companies, Signal will be quite sufficient as a ‘workhorse.’ However, for sensitive negotiations, whistleblower protection, or work in hostile environments, it is essential to define special channels (such as SimpleX or Briar) and clear rules about who uses them and when.

However, a regulatory storm looms on the horizon that could redefine the market. The European Union is actively discussing the introduction of the so-called ‘Chat Control‘ regulation (a proposal for a regulation to combat child sexual abuse). Although it has a noble goal, this proposal in its technical execution suggests the introduction of client-side scanning, a mechanism that would scan messages on the device before they are encrypted.

This is in direct contradiction to the mathematical principles of E2EE encryption advocated by Privacy Guides. Meredith Whittaker, president of Signal, has already publicly threatened that Signal would rather leave the European Union market than agree to the installation of ‘backdoors’ or surveillance mechanisms, as this would destroy the very purpose of the application.

For business users, this creates a paradox. Regulation that is supposed to increase security could actually drive away the only tools that guarantee the technical security of business secrets. In this context, transitioning to decentralized tools and ‘Zero-Trust’ models is not just a matter of immediate security, but also a long-term assurance that your data remains yours, regardless of what the legislator decides, because the mathematics of encryption does not succumb to political compromises. Security is an investment, and in the near future, privacy is the only asset that once lost, cannot be bought back.