What is Signal and why you should use the most secure messaging app

Signal has established itself as one of the most secure and privacy-focused messaging apps. The current context of digital communication increasingly demands tools that prioritize the protection of personal information, and Signal has managed to capture the attention of millions of users concerned about the confidentiality of their messages, especially following the controversy surrounding changes to the privacy policies of competitors like WhatsApp.

In this article you will discover in depth What is Signal, how does it work, and what are its privacy advantages compared to apps like Telegram and WhatsApp?, as well as its limitations, technical operation, and the reasons why experts, activists, journalists and even some governments have turned to it for their most sensitive communications.

The importance of privacy in today's messaging

Instant messaging has become the preferred channel to communicate with friends, family, colleagues, clients or strangers, which increases the exposure of our private information on the network exponentially.

Just as you wouldn't leave your front door open to strangers, you should be aware that Digital messages need to be protected to prevent prying eyes, unauthorized access, and, above all, to prevent companies or cybercriminals from accessing sensitive data or using it for commercial purposes.

The fundamental difference between privacy in real life and in digital environments is that users often have no control or even knowledge of who has access to their messages. This is where Signal comes into its own with a radically different approach: Privacy is not an optional feature, but the central pillar of the platform.

End-to-end encryption: the heart of Signal

Signal's main differentiating factor is its end-to-end encryption (E2EE), which guarantees that Only the sender and receiver can read the messages, photos, videos, or listening to calls. Not even Signal developers or intermediary servers can access the content; everything is encrypted to the point where it's unbreakable by any third party.

This technology is based on the signal protocol, considered one of the most robust and studied encryption systems today. Its effectiveness is such that Apps like WhatsApp and Facebook Messenger have adopted the Signal Protocol to protect their chats..

While in Telegram end-to-end encryption is only available in the secret chats (and by default, most of your conversations are not fully encrypted), on Signal All conversations, calls and files sent are protected by E2EE from the first second, without the user having to configure anything additional.

This encryption uses a system of temporary and permanent keys that are constantly being renewed. Each message uses different keys to prevent previous or future messages from being decrypted even if one key is compromised at some point. This is called perfect secret forward.

In addition, Signal provides advanced features to enhance privacy, such as the sealed sender, which makes it extremely difficult for third parties to access even the metadata about who is talking to whom.

What is Signal and how does it work?

Signal is a Secure, open-source instant messaging and calling application developed by a non-profit foundationIts mission is to enable anyone, anywhere in the world, to communicate securely and privately, without their information being used for commercial or advertising purposes.

The application was created by Moxie marlinspike and has the financial backing of the Signal Foundation, founded by Brian Acton, one of the co-founders of WhatsApp, who decided to invest in a tool without advertising monetization or massive data collection.

Signal is available for Android, iOS, and also has desktop versions for Windows, Mac, and Linux.Its interface is simple and intuitive, similar to other messaging apps, making the transition easier for new users.

To register, only a phone number is required (apart from the new username system that enhances anonymity), and the app doesn't ask for any additional personal information. The number is used solely as an identifier and is not visible to other users if you prefer.

Advantages and advanced features of Signal that you should know

• End-to-end encryption for everything: Messages, voice and video calls, group chats, files and photos, all protected without exception.
• Open source and audited: Any expert can examine Signal's operation to identify vulnerabilities or improve security.
• No advertising or trackingSignal doesn't collect metadata about your communications (such as who you're talking to, when you're talking, or where you're talking from) and limits the collection of personal information to the bare minimum (such as your phone number or username).
• Disappearing messages: You can set messages to self-destruct after being read or after a custom time, making it difficult for anyone to recover them.
• Does not save copies in the cloud: Messages only exist on the sending and receiving devices. Once deleted, they are not stored on any external servers.
• secure authentication: You can lock the app with a PIN, password, or biometric data (fingerprint or facial recognition), increasing security against device theft.
• Face blurring and image editing: Before sending a photo, Signal lets you blur faces or sensitive areas, add text or stickers, and set the image to only be visible once.
• Advanced group chats: With support for up to 1.000 users, admin features, QR code or link invitations, mentions, disappearing messages by group, and advanced access controls.
• Lock Screenshots: You can prevent screenshots from being taken within the app to protect the privacy of your conversations.
• Personal notes and self-messaging: Serves as an encrypted and secure notepad to store private information, files, or reminders.
• Advanced image editing from the app: Crop, blur, write, stickers, and more tools to protect or personalize photos.
• Share large filesSignal allows you to send any type of file without the strict size limits of other apps.
• Contact verification by QR code or security numbers: To authenticate that you are speaking only to the right person, you can compare a secure code with your interlocutor.
• True cross-platform support: Chat synchronization (without uploading messages to the cloud) between mobile and desktop, with security warnings to avoid malware vulnerability on computers.
• Advanced Privacy in Notifications: You can install Signal so that notifications do not show your name or message on the lock screen.

Options as advanced as the private keyboard (prevents the keyboard from collecting what you type), the record lock (protects your account from unauthorized access from other devices) or the exclusively local and encrypted backups, further reinforce the focus on protection against any threat.

Why is Signal preferred by journalists, activists, and cybersecurity experts?

Signal has positioned itself as the essential tool for users who need privacy and confidentiality in their communications.Journalists, human rights defenders, political activists, and even public officials have embraced Signal, believing it to be the best way to prevent mass spying, surveillance by companies or governments, and metadata tracking.

European Union institutions have recommended its use, and various organizations around the world have opted for Signal to protect confidential sources or avoid retaliation for political opinions.

The approach “safe by defaultSignal's "Integrated Messaging" technology, combined with the ability to verify the authenticity of interlocutors and the transparency of its source code (which is audited regularly), make it the international benchmark for truly private messaging.

Differences between Signal, Telegram, and WhatsApp in terms of privacy protection

Users often wonder if Telegram and WhatsApp offer a level of privacy comparable to Signal. Although these apps have improved their security standards by integrating end-to-end encryption, there are key differences What you should consider:

• On Signal End-to-end encryption is mandatory for all chats, individual, group, and calls. There is no option to disable it. and privacy is absolute.
• On WhatsApp Signal encryption is enabled by default for chats and calls, but as part of Meta, the app collects usage metadata and shares information with other companies in the group, which may compromise some of your privacy.
• On Telegram End-to-end encryption is only applied in “secret chats”, i.e. You have to create a special conversation so that the protection is complete.Most normal chats go through Telegram's servers and can be technically accessed by the company.
• Signal does not require personal data beyond the phone number. and now allows registration by username, while other competitors can register additional information such as contact lists, profile photos, location, etc.
• Signal stores as little information as possible on servers and delete any additional data as soon as possible. WhatsApp and Telegram maintain backups in the cloud, which poses a risk in the event of a breach on those platforms.
• Audit level and transparencySignal's source code is 100% publicly available, while WhatsApp doesn't publish its source code, and Telegram only partially publishes some features.

The result is that Signal provides a stricter privacy model, avoiding any mediation or mass storage of your data, protecting both content and metadata, and backing up its promises with open, verifiable technology.

Disadvantages and limitations of Signal

Although Signal represents the benchmark in privacy, It presents some drawbacks for the average user that you should keep in mind:

• Requires phone number or username for registration, which may be uncomfortable for those who prefer complete anonymity (although more advanced systems based solely on aliases are being developed).
• Lower critical mass of users: It's not as popular as WhatsApp or Telegram, so when you install it you might not find all your contacts immediately active.
• There are no public groups or mass channels As in Telegram, all groups are private and require an invitation.
• Limitations in social functionsSignal prioritizes security over integration with other platforms, limiting third-party features or social extensions.
• Depends on a stable internet connection and in some countries you may face temporary blocks, although there are techniques to circumvent them.
• Vulnerability to human error or malware- If the device is infected with malware (keyloggers, spyware, etc.), the encryption security is not sufficient, as messages can be intercepted before or after encryption.

These limitations are the price of real security and absolute control by the userFor most people, its impact is minimal compared to the privacy benefits Signal provides.

How to get started with Signal: installation and first steps

1. Download the app from the Google Play Store, App Store, or from the official website for desktop..
2. Register by entering your phone number, which will serve as an identifier and for initial verification.You can set up a username later so you don't have to reveal your number to others.
3. Set up a security PIN which will protect access to your account and settings.
4. Add a profile picture, if you want. Signal does not share this image with its servers.
5. Invite your contacts to Signal- The app automatically detects (via local verification) who uses Signal in your address book and only allows you to communicate securely with them.
6. Explore privacy settings: You can customize how notifications, the private keyboard, biometric locks, message deletion, and many other key security features work.

In just a few minutes, you'll be ready to use Signal as your primary secure messaging tool.

Frequently asked questions about Signal and its safe use

• Is Signal free? Yes, the app is completely free, with no hidden costs or ads, and is funded by donations and grants.
• What information does Signal collect? Only your phone number (or username) is used to identify you; it doesn't collect your location, full contact list, or activity data.
• Why should you check Signal's security numbers? To be absolutely certain that no one has intercepted the communication between you and your interlocutor, it is advisable to scan the QR code or compare the security number with the other person's, especially in sensitive conversations.
• Is Signal perfect and infallible? No system is. Its robustness depends on the devices it runs on being up-to-date, protected, and free of malware. If you believe you are an advanced target for state attacks, also follow best practices recommended by specialized organizations (EFF, Freedom of the Press Foundation).
• Are there backup copies of the messages? In Signal these copies they never upload to the cloudIf you make a copy, it's stored encrypted on your own device, and only you have the key to restore it to another phone.

Related article:

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Is Signal recommended for government or public communications?

One of the most relevant recent debates around Signal has arisen from high-profile incidents, such as the case in which Senior government officials used Signal to coordinate sensitive military operations and accidentally invited outside journalists to the chats.

These situations have shown that, although Signal offers the best privacy for individual users, It is not suitable for managing classified information or for fulfilling legal record preservation obligations in the public sector.Its design prioritizes the secure deletion of messages and the impossibility of recovery, which conflicts with regulations regarding archiving and controlling public information in governments and large institutions.

Therefore, Signal is The best choice for personal communications, private professional communications and contexts where confidentiality is key, but it should not be used to handle official information that requires archiving or monitoring by law.

Signal represents a revolution in digital privacy protection and has earned a reputation as the "gold standard" in secure messaging. Its transparency, non-profit focus, and constant improvements make it the best alternative for those who don't want their conversations tracked, analyzed, or exploited for commercial purposes. If you value your privacy and want an app that puts your security first, Signal is undoubtedly the option that best suits the needs of the digital age.