Signal vs WhatsApp vs iMessage: What Each Company Says About Encryption
All three say they end-to-end encrypt your messages. Here's what their own documentation says about the details: business chats, verification and platforms.
In this article
How we put this together: this is a research-based comparison drawn from each company's own security documentation, linked below. We haven't run hands-on tests or independent audits, and we don't rank these services on claims we can't check.
Signal, WhatsApp and Apple's iMessage all say your messages are end-to-end encrypted, meaning only the people in the conversation can read them. The differences are in the details, so here's what each company's own documentation says.
Signal
Signal says its conversations are always end-to-end encrypted: "Privacy isn't an optional mode." Users can check they're talking to the right person by comparing safety numbers. Signal also says the complete source code for its apps and its server is on GitHub, so anyone can inspect it.
WhatsApp says personal chats and calls are end-to-end encrypted automatically, using the same Signal encryption protocol, and that it can't read or listen to them. Its help page lists exceptions:
- When a business uses optional services from Meta to manage chats, WhatsApp doesn't consider those chats end-to-end encrypted. It says it shows this clearly in the chat.
- Chats with third-party agents, which are managed by a Meta service, aren't considered end-to-end encrypted either.
- Payments aren't end-to-end encrypted, because banks need the transaction details.
To verify a chat, open the contact, tap Encryption, and compare the QR code or 60-digit number. WhatsApp says it also checks these codes automatically using "key transparency."
iMessage
Apple's Platform Security guide says iMessage content and attachments are end-to-end encrypted, that Apple doesn't store them, and that Apple can't decrypt them. Each device creates its own encryption keys when iMessage is turned on. iMessage only runs on Apple devices.
At a glance
| Signal | iMessage | ||
|---|---|---|---|
| E2EE by default (personal chats) | Yes, always | Yes | Yes |
| Documented exceptions | None stated | Some business chats, third-party agents, payments | Not covered in the page we cite |
| Contact verification | Safety numbers | Security code/QR, key transparency | Not covered in the page we cite |
| Source code published | Clients and server | Not stated | Not stated |
| Platforms | Cross-platform | Cross-platform | Apple devices |
How to choose
The app your contacts already use matters most. If you want the strongest default with the fewest exceptions, Signal's documentation makes the broadest claim. On WhatsApp, look for the labels on business chats. Encryption only protects messages in transit and on the company's servers. It doesn't protect an unlocked phone, so use a strong screen lock too.
More: Reviews · Cybersecurity.
Sources
- Is it private? Can I trust it? — Signal Support · Primary source · accessed October 16, 2026Supports: Always E2EE; safety numbers; client and server source on GitHub
- About end-to-end encryption — WhatsApp Help Center · Primary source · accessed October 16, 2026Supports: Default E2EE personal chats; Signal protocol; business optional services and third-party agents not E2EE; payments not E2EE; security code 60 digits/QR; key transparency
- iMessage security overview — Apple Platform Security · Primary source · accessed October 16, 2026Supports: E2EE; Apple doesn't store content and can't decrypt; Apple devices; per-device keys
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