Signal, WhatsApp, and Telegram get lumped together in casual conversation as “the encrypted messaging apps,” but that framing hides a real architectural split. Two of the three build end-to-end encryption (E2EE) into every default chat. The third encrypts only a feature most people never turn on. Here’s what each app’s own documentation says about how its encryption actually works, what’s encrypted by default versus opt-in, and what each company can see even when your messages can’t be read.
At a Glance
| App | Default chat encryption | Group chat encryption | Backup encryption | Open source | Metadata collection |
|---|---|---|---|---|---|
| Signal | End-to-end by default, every chat and call (Signal Protocol) | End-to-end by default | Opt-in; end-to-end encrypted when enabled (on-device passphrase or cloud recovery key) | Fully open source — client and server | Minimal by design: no stored contact/social graph, sealed sender hides who’s messaging whom from Signal’s own servers |
| End-to-end by default, using a licensed implementation of the Signal Protocol | End-to-end by default | Opt-in; off by default. Standard Google Drive/iCloud backups are not end-to-end encrypted by WhatsApp | Client apps are closed source; only the underlying protocol library is open | Phone number, contacts (if uploaded), device/connection data, usage metadata (who you interact with, how often, for how long), shared across Meta’s family of companies | |
| Telegram | Not end-to-end by default — only opt-in “Secret Chats” are E2E; default “Cloud Chats” use server-client encryption (MTProto) | Not end-to-end — group chats are Cloud Chats only; Secret Chats don’t support groups | No dedicated E2E backup; Cloud Chat history is stored on Telegram’s servers by design | Client apps are open source; server-side code is not published | Cloud Chat data is stored on Telegram’s servers (split across jurisdictions, per Telegram); Secret Chat content is not retained |
Signal: Encryption Is the Entire Product
Signal is built around the Signal Protocol, the open-source cryptographic protocol it developed and that the Signal technology documentation lists as a public specification with freely available software libraries (including libsignal on GitHub). Every one-to-one chat, group chat, voice call, and video call is end-to-end encrypted by default — there’s no setting to turn on, because there’s no unencrypted mode to fall back to.
Signal also goes further than encrypting content. Its “sealed sender” feature, described in Signal’s own technical blog post, encrypts the sender’s identity inside the message envelope itself, so Signal’s servers handle delivery without being able to read who sent a given message — only who it’s being delivered to. Signal states it is designed to retain as little user data as possible: by its own account, it does not store users’ contact lists, conversation lists, location, profile avatars, or group membership information. Chat backups are optional. Signal’s support documentation describes two mechanisms — an on-device backup protected by a local passphrase, and an optional “Secure Backup” restored via a recovery key — both end-to-end encrypted, neither on by default.
WhatsApp: Signal’s Encryption, Meta’s Metadata
WhatsApp’s end-to-end encryption is not a separate invention — it’s a licensed implementation of the Signal Protocol. Signal’s own 2016 announcement confirmed the integration was “fully complete” across WhatsApp’s chats, group chats, attachments, voice notes, and voice calls, on all supported platforms. WhatsApp’s own “End-to-End Encryption” page states plainly that “every call you make, and every message, photo, video, file, and voice message you send, is end-to-end encrypted by default, including group chats” on current app versions. On the encryption math itself, WhatsApp and Signal are effectively equivalent.
Where the two diverge is backups and metadata. WhatsApp’s end-to-end encrypted backup option — detailed in a Meta engineering post — is opt-in: it generates a unique backup key, which you either store yourself or protect with a password held in an HSM-based vault that WhatsApp says it cannot read. Without opting in, chat backups still go to Google Drive or iCloud, and WhatsApp’s own description of that default path says only that “WhatsApp does not have access to these backups, and they are secured by the individual cloud-based storage services” — not that they’re end-to-end encrypted by WhatsApp. On metadata, WhatsApp’s privacy policy is explicit: it collects your phone number, contact list (if you opt into contact upload), device and connection details, and usage information covering how you interact with others and the timing, frequency, and duration of that activity — and that data is shared with and received from other Meta Companies for purposes including safety, personalization, and advertising across Meta’s products. None of that touches message content, but it is a meaningfully larger metadata footprint than Signal’s.
Telegram: Encryption Is the Exception, Not the Rule
This is where the comparison usually goes wrong in casual coverage, because Telegram markets itself as a security-focused app and does offer real end-to-end encryption — just not for the chats most people actually use. Telegram’s own FAQ and developer documentation describe two distinct chat types. “Server-client encryption is used in Cloud Chats (private and group chats),” per Telegram’s FAQ — meaning the connection between your device and Telegram’s servers is encrypted (via Telegram’s MTProto protocol), but Telegram’s servers can access the plaintext content, since that’s what lets messages sync across your devices and live in the cloud. Telegram’s end-to-end encryption documentation defines Secret Chats separately, describing them as “one-on-one chats wherein messages are encrypted with a key held only by the chat’s participants” — and critically, Secret Chats are device-specific, not synced to the cloud, and not available for group chats at all.
In practice, that means the default chat you open with a contact, and every group or channel on Telegram, is not end-to-end encrypted — Telegram’s own servers can technically access that content, even if the company’s stated policy is not to hand it over without legal compulsion in multiple jurisdictions. Getting actual E2EE on Telegram requires deliberately starting a Secret Chat with each contact individually, and it’s simply unavailable for groups. Telegram’s client applications (such as Telegram Desktop) are published as open source, but the server-side code that handles Cloud Chats is not, so independent researchers can’t verify server-side behavior the way they can with Signal’s fully open stack.
Comparison Table
| Property | Signal | Telegram | |
|---|---|---|---|
| Encryption protocol | Signal Protocol (original implementation) | Signal Protocol (licensed implementation) | MTProto (Cloud Chats); separate E2E layer for Secret Chats only |
| E2E by default for 1:1 chats | Yes | Yes | No — must manually start a Secret Chat |
| E2E available for group chats | Yes, by default | Yes, by default | No — not supported in any form |
| Who can see message content | Only participants, even with server access | Only participants, even with server access | Telegram’s servers can access Cloud Chat content; only participants for Secret Chats |
| Sender identity hidden from the service | Yes, via sealed sender | Not described in public documentation | No |
| Company’s metadata visibility | Very limited by design | Phone numbers, contacts, usage patterns; shared across Meta | Full Cloud Chat metadata and content stored server-side |
Trade-Offs
No app here is strictly “best” for every use case. Signal’s minimal metadata collection and fully open-source stack give it the strongest privacy guarantees on paper, but that also means fewer convenience features tied to a social graph the app deliberately doesn’t retain, and it has a smaller install base than the other two. WhatsApp’s cryptography is just as strong as Signal’s for message content — the Signal Protocol doesn’t get weaker because Meta licenses it — but its business model depends on metadata and cross-app data sharing that Signal’s doesn’t, and its backups require an extra opt-in step to get the same end-to-end protection Signal and WhatsApp both apply to live chats by default. Telegram’s biggest advantage is features — large public channels, bots, massive group sizes, cross-device cloud sync — and all of those features exist specifically because Cloud Chats aren’t end-to-end encrypted; building sync and 200,000-member groups on top of true E2EE is a much harder problem that Telegram has not solved for its default chat type. Treating Telegram as “the secure one” because it talks about encryption, without checking whether a given chat is actually a Secret Chat, is the most common mistake in this comparison.
The Bottom Line
If end-to-end encryption by default, for every chat type, with the smallest possible metadata trail, is the priority, Signal is the most defensible choice, backed by a fully open-source client and server. WhatsApp offers the same underlying encryption for message content and is far more convenient if the people you talk to already use it, but accept that Meta collects and shares meaningfully more metadata than Signal does, and that you have to manually opt into end-to-end encrypted backups to close that one gap. Telegram is the odd one out: despite its security-forward branding, the chats and groups almost everyone actually uses on it are not end-to-end encrypted at all — only one-on-one Secret Chats are — so it should be evaluated as a cloud-synced messaging and broadcast platform with an optional, limited encryption mode, not as an encrypted messenger by default.
FAQ
Is Telegram end-to-end encrypted?
Only in Secret Chats, which are one-on-one, device-specific, and not synced to the cloud. The default chats and all group chats/channels use server-client encryption (MTProto) instead, meaning Telegram’s servers can technically access that content.
Is WhatsApp’s encryption as strong as Signal’s?
For message content, yes — WhatsApp uses a licensed implementation of the same Signal Protocol, confirmed complete by Signal in 2016 and covering chats, group chats, and calls. The difference is in metadata collection and backup defaults, not the core encryption math.
Are WhatsApp chat backups encrypted?
Only if you opt into WhatsApp’s end-to-end encrypted backup feature, which uses a user-held key or password-protected vault. Without opting in, backups go to Google Drive or iCloud, and WhatsApp’s own documentation says those are “secured by the individual cloud-based storage services” rather than end-to-end encrypted by WhatsApp itself.
Can Telegram read my group chats?
Group chats on Telegram are Cloud Chats by design — Secret Chats don’t support groups at all — so Telegram’s servers can technically access that content, consistent with how Telegram’s own FAQ describes server-client encryption for Cloud Chats.
Which app collects the least metadata?
Signal, by a wide margin. Its own documentation states it does not store contact lists, conversation lists, group membership, or location, and its sealed sender feature hides sender identity from its own servers. WhatsApp collects phone numbers, device data, and usage patterns that are shared across Meta’s companies. Telegram stores full Cloud Chat content and metadata on its own servers.
For a related look at securing the accounts behind these apps in the first place, see our passkeys vs. two-factor authentication comparison, and our breakdown of password managers for everything else tied to those same accounts.
Sources
- Signal: Technical documentation and the Signal Protocol
- Signal: Technology preview — Sealed sender for Signal
- Signal Support: Backups and Device Transfers on Signal
- Signal: WhatsApp’s Signal Protocol integration is now complete
- WhatsApp Blog: End-to-end encryption
- Meta Engineering: WhatsApp end-to-end encrypted backups
- WhatsApp Privacy Policy
- Telegram FAQ
- Telegram: End-to-End Encryption, Secret Chats
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