ZeroMem vs Signal
Signal is the best-known secure messenger: free, open source and run by a nonprofit. Both Signal and ZeroMem (零憶) encrypt messages and calls end to end, and both let you verify a contact in person with a 60-digit safety number or a code to scan. They differ in what is kept, where your identity lives, and what happens on calls.
| Feature | ZeroMem | Signal |
|---|---|---|
| End-to-end encrypted messages and voice calls | Yes | Yes |
| Message history on your device | None: messages live in memory only | Kept, encrypted; disappearing messages are optional |
| Message backups | None | Optional, encrypted, on the device or on Signal's servers |
| Messages for an offline recipient | Not delivered rather than stored | Held encrypted on the server until delivered |
| Identity locked with a YubiKey / FIDO2 key | Yes | No |
| Screenshots and screen recording blocked | Always, on Windows and Android | On by default on Windows 11; a setting on Android |
| Voice changer on calls | Yes, on by default | No |
| How you add contacts | Username or code, no phone number; both sides agree first | Phone number or username |
| Platforms | Android 10 or later, Windows 10 or later (64-bit) | Android, iOS, Windows, macOS, Linux |
| Price | Paid, per account; organisations buy seats and manage their own members | Free; more backup storage is an optional paid plan |
Who ZeroMem is for
People and organisations for whom any stored copy of a conversation is a risk, and who want nothing left on a phone or a server afterwards.