Signal – Private Messenger

What is Signal?

Signal is the world’s most secure and privacy-focused messaging application that provides end-to-end encrypted text messaging, voice calls, video calls, and file sharing without collecting user data, selling advertisements, or tracking conversations—making it the gold standard for private communication trusted by journalists, activists, security researchers, government officials, and privacy-conscious individuals worldwide. Developed by Signal Foundation, a non-profit organization founded by cryptographer Moxie Marlinspike and WhatsApp co-founder Brian Acton in 2018, Signal has evolved from TextSecure encrypted messaging app into comprehensive communication platform used by over 100 million people who refuse to compromise privacy for convenience. With endorsements from Edward Snowden, the Electronic Frontier Foundation, and security experts globally, Signal proves that messaging apps can provide both exceptional security and user-friendly experience without exploiting user data for profit.

Signal excels through uncompromising encryption architecture—every message, call, photo, and video is end-to-end encrypted using the open-source Signal Protocol (formerly Axolotl), meaning only sender and recipient can decrypt content with Signal’s servers unable to access message contents, metadata about who talks to whom, or any information beyond delivery routing. Unlike WhatsApp (which uses Signal Protocol but collects metadata) or Telegram (which doesn’t encrypt chats by default), Signal encrypts everything automatically with no “secret chat” mode required and collects virtually no user data—registration requires only phone number, with no names, contact lists, groups, or messages stored on Signal’s servers. The non-profit structure ensures no advertising, no data mining, and no business model requiring user exploitation. For anyone prioritizing communication privacy—journalists protecting sources, activists organizing movements, professionals discussing confidential matters, or simply users valuing privacy as fundamental right—Signal provides military-grade security in accessible package.

Beyond security, Signal offers modern messaging features including disappearing messages with customizable timers, group chats supporting thousands of members, high-quality voice and video calls, screen sharing, stickers and GIFs, message reactions, voice messages, link previews, and cross-device synchronization across phones and desktops. The software runs on Android, iOS, Windows, macOS, and Linux with consistent encryption across platforms. Unique privacy features include sealed sender hiding sender identity from Signal servers, view-once photos and videos, registration lock preventing SIM-swapping attacks, and relay calls hiding IP addresses. Open-source code allows independent security audits verifying encryption implementation. For users seeking WhatsApp or Telegram alternative prioritizing privacy over features, or anyone simply wanting messaging app that respects users rather than treating them as products, Signal delivers encrypted communication that should be the standard rather than exception.

Key Features

• End-to-End Encryption: All messages, calls, and media encrypted by default with Signal Protocol—the industry gold standard.
• Minimal Data Collection: Only phone number stored—no contacts, groups, messages, or metadata collected.
• Encrypted Voice/Video Calls: High-quality encrypted calls without quality degradation from encryption overhead.
• Disappearing Messages: Set timer for messages to automatically delete after specified time on all devices.
• View-Once Media: Send photos and videos that disappear after single viewing.
• Group Chats: Encrypted group messaging supporting thousands of members with admin controls.
• Screen Sharing: Share screen during video calls with end-to-end encryption.
• Sealed Sender: Hide sender identity from Signal servers for maximum metadata protection.
• Registration Lock: PIN protection prevents SIM-swapping attacks hijacking account.
• Relay Calls: Hide IP address during calls by routing through Signal servers.
• Cross-Platform: Available for Android, iOS, Windows, macOS, and Linux with desktop sync.
• Open Source: Publicly auditable code ensures security claims can be verified independently.
• Non-Profit Foundation: No advertising, no data mining, no business model requiring user exploitation.
• Message Reactions: Emoji reactions to messages with full end-to-end encryption.
• Completely Free: All features available without payment, ads, or premium tiers forever.

What’s New in Signal 2024/2025

• Usernames: Optional usernames allow communication without sharing phone numbers.
• Better Group Calls: Improved group video call quality and performance with more participants.
• Enhanced Desktop App: Better desktop experience with improved sync and performance.
• Improved Backup: Better encrypted backup and restore functionality across devices.
• Better Stories: Enhanced Stories feature with privacy controls and better media quality.
• Performance Improvements: Faster message sending and media loading across all platforms.
• UI Enhancements: Modern interface updates while maintaining simplicity and usability.
• Better Media Quality: Higher resolution photo and video sharing with maintained encryption.
• Enhanced Security: Regular security audits and cryptographic improvements.
• Bug Fixes: Addressed reliability issues and improved stability across platforms.

System Requirements

Android

• Android 5.0 Lollipop or later
• Google Play Services or microG for notifications (or use Signal’s own notification system)
• 50 MB available storage
• Internet connection (Wi-Fi or mobile data)

iOS

• iOS 13.0 or later
• Compatible with iPhone, iPad, and iPod touch
• 50 MB available storage

Windows

• Windows 10 or Windows 11
• 64-bit operating system
• Active Signal account on mobile device (required for setup)

macOS

• macOS 10.12 Sierra or later
• Intel or Apple Silicon (M1/M2/M3) processors
• Active Signal account on mobile device

Linux

• Most modern distributions (Ubuntu, Debian, Fedora, etc.)
• 64-bit system required
• Available as DEB, RPM, or AppImage

How to Get Started with Signal

1. Download: Visit signal.org or install from Google Play Store (Android) or App Store (iOS).
2. Install App: Install Signal on your smartphone—desktop versions require mobile app first.
3. Register: Enter phone number and verify via SMS code sent to your number.
4. Set Up Profile: Optionally add profile name and photo (stored only on your device, not servers).
5. Create PIN: Set up Signal PIN for registration lock and encrypted cloud backups.
6. Find Contacts: Signal shows which contacts use Signal—all encrypted, contacts not uploaded to servers.
7. Start Messaging: Select contact to start encrypted conversation—all messages encrypted automatically.
8. Enable Disappearing Messages: Tap contact/group name > Disappearing messages to auto-delete messages after timer.
9. Link Desktop: Install desktop app > Open Signal on phone > Settings > Linked devices > Link new device > Scan QR code.
10. Explore Privacy Settings: Settings > Privacy to configure read receipts, typing indicators, and other privacy options.
11. Verify Safety Numbers: For sensitive conversations, verify safety numbers to confirm encryption keys match.
12. Try Voice/Video Calls: Tap phone or video icon in conversation for encrypted calls.

Signal vs Alternatives

Pros and Cons

Pros

• Completely Free: All features available without ads, subscriptions, or premium tiers forever.
• Maximum Privacy: Industry-leading privacy with minimal data collection and metadata protection.
• True End-to-End Encryption: Everything encrypted by default using proven Signal Protocol.
• Non-Profit Model: No advertising or data mining—funded by donations and grants.
• Open Source: Publicly auditable code verified by independent security researchers.
• Expert Endorsed: Recommended by Edward Snowden, EFF, and security professionals globally.
• Cross-Platform: Consistent experience across mobile and desktop with encrypted sync.
• Modern Features: Competitive feature set including group calls, stories, and reactions.
• Disappearing Messages: Automatic message deletion provides additional privacy layer.
• No Phone Home: App doesn’t send usage data or analytics to developers or third parties.

Cons

• Smaller User Base: Fewer users than WhatsApp or Telegram requiring friends to switch.
• Phone Number Required: Registration requires phone number (though usernames now available).
• Limited Cloud Backup: Encrypted backups more complex than unencrypted alternatives.
• Fewer Features: Less feature-rich than Telegram for channel broadcasting and bot ecosystem.
• No Multi-Device Initial Setup: Requires smartphone for initial setup before desktop use.
• SMS Integration Removed: No longer handles regular SMS messages alongside Signal messages.

Who Should Use Signal?

Signal is ideal for:

• Privacy Advocates: Users prioritizing privacy and security above all other considerations.
• Journalists: Protecting confidential sources and sensitive communications.
• Activists: Organizing movements without government or corporate surveillance.
• Security Professionals: IT and security experts needing secure communication channels.
• Government Officials: Public servants handling sensitive but unclassified information.
• Healthcare Workers: HIPAA-compliant communication without violating patient privacy.
• Legal Professionals: Attorneys and clients discussing privileged information securely.
• Dissidents: People in authoritarian countries requiring secure communication.
• Privacy-Conscious Users: Anyone valuing digital privacy as fundamental human right.
• WhatsApp Refugees: Users leaving WhatsApp due to Facebook’s privacy policies.

Frequently Asked Questions

Is Signal really more private than WhatsApp?

Yes, significantly more private. While WhatsApp uses Signal Protocol for message encryption (messages themselves are secure), WhatsApp collects extensive metadata including who you talk to, when, how often, device information, IP addresses, and shares this data with Facebook/Meta for advertising. Signal collects only your phone number and last connection time—no contacts, groups, message metadata, or information about communication patterns. Signal’s non-profit structure means no business incentive to collect data, whereas WhatsApp’s integration with Facebook’s advertising ecosystem creates profit motive for metadata collection. For message content security, both are good; for overall privacy, Signal is objectively superior.

Can Signal be hacked or monitored by governments?

Signal’s end-to-end encryption makes message interception extremely difficult—even Signal cannot decrypt messages. However, device-level attacks (malware, keyloggers, unlocked phone access) can compromise any app including Signal. Government agencies with advanced capabilities might exploit zero-day vulnerabilities in Signal or underlying OS, though no public evidence suggests this occurs. Signal’s open-source code allows security researchers to find and fix vulnerabilities quickly. For typical threat models (corporate surveillance, data breaches, mass surveillance), Signal provides excellent protection. For nation-state attackers with unlimited resources, no app provides absolute guarantee—though Signal remains best available option.

Why does Signal require a phone number?

Signal requires phone numbers for spam prevention, account recovery, and ensuring one person = one account without complex username/password systems that create usability barriers. Phone number verification makes mass account creation for spam difficult while keeping signup simple for legitimate users. Signal recently added optional usernames allowing communication without sharing phone numbers with contacts—you can now use username for new contacts while phone number remains for verification only. The phone number requirement is privacy tradeoff balancing security (preventing abuse) with usability (simple registration).

Is Signal safe to use for illegal activities?

Signal is designed to protect privacy and free speech, not facilitate illegal activity. While Signal’s encryption protects message content from interception, using Signal for illegal purposes doesn’t make you immune to investigation—device seizure, informants, metadata analysis, or non-Signal communication can still expose illegal activity. Signal should be used for legitimate privacy needs: journalism, activism, confidential business communication, personal privacy—not to facilitate crime. Privacy is fundamental right, but rights don’t exempt anyone from laws. Signal protects your communications but isn’t “get out of jail free” card for illegal behavior.

Final Verdict

Signal represents the gold standard for private messaging by proving that user privacy and modern features aren’t mutually exclusive—delivering end-to-end encryption, minimal data collection, open-source transparency, and non-profit governance in accessible package that doesn’t require cryptography expertise to use safely. The combination of Signal Protocol encryption (used even by WhatsApp), metadata minimization beyond competitors, expert endorsements from security community, and business model free from advertising incentives creates messaging app that respects users as people rather than data sources to monetize. For anyone serious about communication privacy—whether protecting sources, organizing movements, discussing confidential matters, or simply believing privacy is fundamental right—Signal delivers the secure messaging that should be industry standard rather than privacy-conscious niche.

The smaller user base compared to WhatsApp and Telegram presents network effect challenge requiring friends and colleagues to switch, but Signal’s feature set has matured enough that switching doesn’t mean sacrificing modern messaging conveniences. The recent username addition addresses phone number privacy concerns, while continued development adds features closing gap with feature-rich alternatives. Download from signal.org and experience messaging app that treats privacy as essential feature rather than premium add-on—proving that the most secure messenger can also be free, open-source, and genuinely committed to user interests rather than shareholder profits or surveillance capitalism.