We keep seeing news about data leaks, creepy tracking, or government spying. Lately in July 2025, a women’s dating app called Tea has suffered a data breach. Around 1.1 million private messages and 13000 images including selfies and ID’s were leaked, exposing personal content and putting users at risk. Yes the app is popular and yet it suffered data breaches, so it’s not mandatory that popular apps are always safe.
These days, sending a message isn’t just sending words. There’s a lot more behind every “hey,” photo, or voice call. Someone could be watching, tracking, or even saving your stuff without you knowing.
I’ve personally tested several secure messaging apps and reviewed in-depth audit reports from multiple services (explained later in the article), including those conducted by some of the world’s leading cybersecurity research groups, to evaluate how these apps protect your data.
If you are someone who want to keep your personal/ professional life private the app you use really matters. If you want truly safe messaging, you need the right tool, built with privacy and security at its core.
In this article, You will learn what actually makes a messaging app secure, which ones are worth your trust, what to avoid, and how to keep your chats private without overthinking it.
Chapter 1: Why You Must Keep Your Chats Private?
As explained above, in our daily life we all exchange messages, pictures or videos as well. Sometimes it’s just catching up with someone with casual conversation and rest of the times its more personal like you chatting with your CA about your finances or sharing how you are feeling lately with your therapist. These personal details could be used against you if your messages are compromised. While most of the apps promise security the real question is who apart from sender and receiver can access your messages. This could be the app company, any server or government itself. That’s where end-to-end encryption comes.
Chapter 2: Core Technologies That Protect You
2.1 End‑to‑End Encryption in a Secure Messaging App
The basic definition is only you and the person you’re chatting with can read the messages. Not even the app, company, hackers, or anyone in between can see them just you two.
What’s Happening Behind the Scenes of a Secure Chat
- Encryption Keys: Each users has a public key and a private key. Messages are locked with the receiver’s public key and can only be unlocked using their private key. Still confused? Think of it like a locked mailbox:
- Public Key = the mailbox. Anyone can drop a letter into it.
- Private Key = the key to open the mailbox. Only the owner has it.
- Encryption and Decryption:
- Encryption: When you type a message and send it, before the message leaves your device, message is converted to unreadable code.
- Decryption: This means turning the secret code back into the original message — but only the receiver (the person you’re sending it to) can do it.
- Ex: You write: “Hi!”
→ Encryption makes it look like: “gH9#k@!”
→ Decryption changes “gH9#k@!” back to“Hi!” (but only for the intended person).
- Forward Secrecy: Each message or session uses a new encryption key, so even if one key is compromised, rest other chats are safe. That’s why forward secrecy is a non-negotiable for any secure chat app that claims to prioritize user privacy.
2.2 Zero‑Knowledge Models
Many private messengers store minimal metadata to make the service work properly. Apps with zero-knowledge architecture don’t store or have access to your messages, passwords, or private data. The entire security process (like encryption/decryption, identity verification) happens on your device. In these systems, servers are basically “dumb” messengers. They don’t see the contents or participants. Signal and Session apps stand out for zero knowledge models.
So how does this benefit you as a user?
- With this model, even if the company wants to snoop your messages, they technically cannot.
- Also, the signup for these apps only require username eliminating the need of phone number or email.
2.3 Metadata Countermeasures
In simple terms metadata is a data about your data, such as Who you talked to, when, how long and your IP address. Even if the messages are encrypted metadata can also reveal information about you. That’s why some of the best private chat apps go a step further with strategies like onion routing and dummy traffic etc.
1. Onion Routing
This means your message goes through many stops before it gets to the other person. Each stop only knows where it came from and where it’s going next , kind of like passing a note through a bunch of people, where no one knows the full path. Session implements true onion routing across a decentralized network of Oxen Service Nodes.
2. Padding, Batching, Delays, and Dummy Traffic
This adds extra “junk” data to your messages so they all look the same size. That way, no one watching can guess what’s inside or how long your message really is. This is used by Session again.
Chapter 3: Essential Safeguards in Any Secure Messaging App
3.1 Default Encryption
A secure messaging app should never make you toggle encryption on or off. If encryption is only available in specific modes such as secret chats (like in Telegram app) users can easily forget to activate it leading to unintentional data exposure. Automatic encryption is what truly defines a private messenger you can trust. The gold standard is end-to-end encryption (E2EE) applied automatically to every message, call, and file transfer and this is by default in apps like Signal, Session and Threema. This ensures only the sender and receiver can read or hear the contents no exceptions.
3.2 Forward Secrecy
Even if someone gains access to your device or your encryption keys later (which is not possible if the app has perfect forward secrecy) they shouldn’t be able to read your old messages. Forward secrecy solves this by using ephemeral keys that change frequently. This means each message (or session) is encrypted with a different key. So, even if one key is compromised, past and future messages remain safe.
3.3 Public Code Audits
When cryptographic libraries (these are pre-written codes that developers use) are kept in the dark, no outside expert can verify their safety. The most trustworthy applications post all critical code to public repositories, supply reproducible builds, and commission third‑party audits by respected security firms. When these Audit reports are published people can get the insights.
3.4 Minimum Data Footprint
Consider what are your personal details that app requires to function. As in while signing up , does it need your phone numbers, email ID’s or any official documents to proceed further or just the username is enough. The more your personal data is stored in the app, Its likely to be sold for third parties for marketing purposes.
3.5 Ephemeral Content
Chats that delete themselves after a while are a smart way to reduce risk—especially if you lose your device or it gets in the wrong hands. So, here’s what to look for in a safe messaging app:
- Disappearing messages with a customizable time period.
- Auto-delete attachments and backups after a time you choose.
Chapter 4: Additional Fortifications
4.1 Screen Capture Prevention
Make sure your chat app protects against malware or other apps trying to take screenshots of your conversations. The best platforms block screen captures completely or stop other apps from seeing what’s on your screen. This helps prevent remote hacks and leaks caused by screenshots.
4.2 Two‑Factor and Hardware Keys
Even top-level encryption can’t help if someone logs into your account. That’s why secure apps give you extra ways to prove it’s really you like:
- Codes from an authenticator app
- Text message or voice call codes (less secure)
- Physical security keys for extra safety
4.3 Robust Group Conversation Security
Many services focus on one‑on‑one protection, yet family group chats and team channels often carry crucial data. Look for:
- Dynamic group key rotation: whenever a new member joins or leaves the group, the app should generate a new encryption key (Signal Protocol does this) to maintain forward secrecy—so past messages are not visible to new participants. These are necessary in any app that wants to be considered the most secure chat app for both individuals and teams. This can be seen in WhatsApp, newly joined members cannot see past conversations.
- Granular admin controls: Platforms such as Telegram (with admin permissions) and WhatsApp (restricting forwarding in groups) allow admins to disable message forwarding or limit who can post, reducing leak and spam vectors.
4.4 Anonymous Signup Paths
When you give phone numbers and email ID’s, the app can link back to you just as how your bank accounts are linked to your numbers. So there are apps which needs only a username of your choice to use the app, one such best app is NewsTalk.
Chapter 5: Reviews of Leading Secure Messaging Apps
Lets explore some of the best secure messaging apps in 2025.
5.1: DailyNewstalk: Secret messaging app
Newstalk is a secret messaging app that is hidden behind a news interface. The home page has chosen category of news articles. I couldn’t easily identify where the chat window was while testing the app. The chat window is hidden behind a reload button (long press) at the bottom right which is password protected so that only you can access.
You get encrypted chats and HD voice/video calls features in the app. No metadata is collected, all you need is a username to use the app. Also you need the exact name of the person in the app to initiate the conversation.
The security feature what we can admire here is that the app itself is disguised so its hard for anyone to guess that this is a messaging app. Also the chat notifications appear as breaking news articles so only you know that’s it’s a message. And none of media gets saved in your phone gallery. This could be considered private chat app. Available on both Android and IOS.
There is no public security audit or open-source code to verify the app’s security. Since the app is new, it has smaller userbase and not ideal for large-scale group communications.
5.2: Signal
Signal just promise privacy it delivers it, consistently. From the moment you install it, everything is end-to-end encrypted by default. No fiddling with settings, no guessing. Even group chats and calls are protected using the Signal Protocol, which isn’t just some marketing term it’s been audited, tested, and trusted by security experts for years.
In our test, for both android and IOS from sending texts to making call fast and seamless. I liked that no metadata is retained like who you talk to or when. It doesn’t log IP addresses, and even your contact list is kept private using sealed sender technology. But you will need a phone number to operate this app.
Another standout? No backups to third-party clouds. Instead, Signal offers local encrypted backups only you can decrypt. And being open-source, its code is publicly reviewed by the cryptography community—something most apps still shy away from.
5.3: Threema
Threema is fully compliant with the European privacy legislation (GDPR). Threema uses the trusted open-source NaCl cryptography library (well-respected open-source library known for its speed, security, and reliability in end-to-end encryption) for encryption. Group memberships and contact lists are managed on the phones and not stored in servers. There are no ads or trackers in the app, also after having several tests calls no metadata was collected.
Here Chats, files, calls—everything is encrypted from start to finish. We installed the app and while signing up phone number or email was not asked, you can use this app anonymously with random Threema ID.
Since the app’s source code is open for everyone, and experts in the industry are regularly commissioned to run audits, this app (Android and IOS) can be trusted. Here is the 2024 audit by Cure53 of the new desktop app.
5.4: Wire
Wire collects minimal metadata—no access to message contents or contact lists. The only stored information may include account registration data (like an optional email or phone number) and basic device identifiers, used solely to sync your account across devices. Your messages are end-to-end encrypted, and any temporary data stored on Wire’s servers is deleted immediately after delivery.
Wire is a Swiss-based, fully open-source messaging app ( available in GitLab ), trusted by organizations across Europe for its compliance with GDPR, ISO 27001/27701, and NIS2 standards ( General data protection regulation is a privacy law in Europe that protects how users data is collected , used and stored). It supports both cloud and self-hosted deployments. Its encryption is built on Proteus, a custom implementation of the Double Ratchet protocol (derived from Signal’s Axolotl/Signal Protocol), using primitives like ChaCha20, Curve25519, HMAC‑SHA256, all powered by libsodium.
To ensure real-world security, Wire underwent independent audits by Kudelski Security and X41 D-Sec, covering all platforms (iOS, Android, desktop, and web). These audits found only low-to-medium severity issues, with no critical vulnerabilities, and all issues were addressed promptly.
5.5 WhatsApp
WhatsApp is pretty famous, I use it , my family does and literally all the people I know. Check the stats here. WhatsApp use end-to-end encryption by default for chats, calls, and media. Although WhatsApp is not a open-source code, its protocol is. It uses Signal protocol.
WhatsApp collects your metadata like timestamps, device identifiers, and contact lists (if you give permission) mostly to make the app work smoothly and to avoid spam. But what about the message contents? these cannot be read by WhatsApp and neither saved on servers once the message is delivered. Learn more about WhatsApp security features and WhatsApp lock chat.
However your WhatsApp cloud backups are not E2EE by default. You can fix this by , Go to settings > Chats > Chat backups > End-to-end Encrypted Backup.
5.6 Telegram
Telegram uses custom encryption protocol called MTProto , which encrypts messages between your device and Telegram’s servers. This means standard and group chats are not end-to-end encrypted and can be technically accessed by Telegram since they are stored in Telegram servers.
But Telegram also features “secret chat’ mode which is end to end encrypted, and stays only on the device from which it is sent as in no cloud sync. Also you can set timers to delete the messages after sent.
Its worth noting that the Telegram is not open-source code and MTProto has not undergone the same level of independent cryptographic auditing as the Signal Protocol.
Chapter 6: Warning Signs You Can’t Ignore
1. Server-Stored Decryption Keys
Apps like Facebook messenger, Viber store encryption keys on their servers. I know Facebook messenger is a very popular social media app, however if the servers breached, your messages could be exposed. So here end to end encryption is not applicable when the providers can your keys.
2. Proprietary or Undocumented Encryption
Certain apps like Bigo live, WeChat use closed-source or homegrown cryptographic algorithms. Meaning nobody can verify them, you have to trust what providers say about their apps. Whereas Signal Protocol and Lokinet can be reviewed by any external security researchers.
3. Excessive Metadata Logging
We all use WhatsApp and you definitely need a phone number to use the app. Some apps log your contact list, IP address, device fingerprint, and timestamps of every interaction — even if your messages are encrypted. This metadata can reveal your network of contacts, usage patterns, and location history, and is often retained indefinitely.
4. AdTech Ties & User Profiling
Isn’t it obvious that we are watched like a hawk? Whatever we plan to buy are often displayed in most of the social media apps that we use daily. So Apps that integrate with ad networks like Meta Audience Network or Google AdMob often siphon behavioral data — like typing speed, frequency of use, and app interactions — to build advertising profiles. If the app monetizes through ads, your privacy is the product.
- Opaque Privacy Claims: If claims lack evidence such as published audits or source snapshots, assume they’re marketing fluff.
Chapter 7: How to choose the Right Secure Messaging App
Not every conversation needs military-grade encryption. But some absolutely do.
7.1: Casual chatters looking for privacy.
For people just tired of apps tracking everything—there are safer options than the default messenger.
Use WhatsApp which comes with default end-to-end encryption or Telegram’s secret chat feature which is again E2EE.
Additionally you can use disappearing messages for sensitive conversations and make sure to have a biometric lock to access the device and apps. Plus skip the cloud backups that are not encrypted.
Also if you want to go a step further and pretend as if you are not texting but just using a app , go for Newstalk app. This is disguised as a news app and the chat window is hidden and password protected.
Check this article on which is the best private messaging app when compared , Signal Vs Telegram Vs DailyNewsTalk
7.2: Business Conversations That Need To Stay Confidential
Handling sensitive client info or workplace conversations? You’ll need something stronger and more compliant.
Based on my testing, go for Signal or Threema. Both these apps are end-to-end encrypted. Signal doesn’t store your metadata and it can host up to 1000 members. On the other hand Threema doesn’t require a phone number or email ID’s to work. Threema Work, the enterprise version, is used by the Swiss Army and several EU government agencies. It can host up to 256 members.
Chapter 8: Agree to terms and policies.
Tapping “Accept” without reading the terms is common. But that click often gives apps broad access—to your location, contacts, photos, and more—sometimes far beyond what’s needed. Mozilla study found nearly 80% of top Play Store apps have misleading or inaccurate data-safety disclosures.)
8.1: Users Often Misunderstand What They’re Agreeing To
Studies show many users don’t grasp permission prompts. In a study of Android users, nearly 80% felt unsure about why apps asked for certain permissions, and many gave consent without understanding the implications. Another study (USENIX) found users frequently ignore app warnings or tap through permission requests—creating privacy and security risks without realizing it.
Even apps with “privacy labels” can be misleading. Mozilla’s analysis revealed that around 16 out of 40 top Android apps earned a “Poor” rating—meaning their privacy policy and what they declared for Google’s Data Safety form didn’t match.
8.2: What This Means for Security
- Apps may collect or share sensitive data—even if they don’t need it for core features.
- Clicking “Agree” can expose personal info without effective oversight.
- App store labels aren’t always verified; developers self-report, which can lead to gaps.
8.3: Agreeing to Terms & Conditions
- What data is collected and why: Check what kind of personal data the app collects (contacts, location, messages, etc.) and how it will be used.
Source: Federal Trade Commission (FTC) - Whether your data is shared with third parties: Look for mentions of “affiliates,” “advertising partners,” or “analytics providers.” Many free apps monetize data by sharing it.
Source: Consumer Reports - End-to-End Encryption (E2EE): For messaging apps, make sure E2EE is offered by default and not just for “secret” chats.
Example: Signal offers E2EE by default — Signal Privacy Overview - User control over data: Can you delete your account and all associated data? Can you download a copy of your data?
Source: General Data Protection Regulation (GDPR) Article 17 – Right to Erasure - Whether permissions match the purpose: Be cautious if a messaging app asks for location, camera, or microphone access without a clear reason.
Study: The Hidden Side of Mobile Permissions (ACM 2022) - Updates and changes to policies: See if the app will notify you about policy changes or data breaches.
Source: California Consumer Privacy Act (CCPA)