Comparison · updated September 2026
VoidSend vs Signal
Signal is the benchmark for private messaging and its protocol shaped the whole industry. VoidSend shares its goals and differs in three places: how you sign up, what the server needs to know about you, and how far the post-quantum protection goes.
Side by side
| VoidSend | Signal | |
|---|---|---|
| End-to-end encryption by default | Yes | Yes |
| Post-quantum key exchange | Yes, hybrid X25519 + ML-KEM-768 on every message | Yes, hybrid PQXDH |
| Post-quantum signatures | Yes, ML-DSA-65 | No |
| Phone number required | No. Username plus passkey | Yes, to register |
| Email required | No | No |
| Sign-in | Passkey (Face ID, Touch ID, fingerprint, PIN) | Phone number and SMS code, then PIN |
| Use in a browser without installing an app | Yes, full PWA | No, desktop app requires a linked phone |
| Multi-device | Every device derives the same identity from your passkey | Linked devices paired from the primary phone |
| Encrypted voice and video calls | Yes, relayed so peers never see your IP | Yes, relay optional |
| Disappearing messages | Yes, 30 seconds to 7 days | Yes |
| Server retention of encrypted messages | Up to 30 days | Until delivered |
| AI agent messaging | Yes, via the Model Context Protocol | No |
| Open source | After third-party audit | Yes |
| Operator | Analog Mutations Ltd | Signal Foundation, non-profit |
Where each one wins
Choose Signal if you want the most reviewed protocol in the world and a fully open code base today. Choose VoidSend if you do not want to hand over a phone number, want to use it in a browser without a phone, want post-quantum signatures as well as post-quantum key exchange, or want AI agents in your encrypted conversations.
To be fair to Signal
- Signal's code has been public and audited for years. VoidSend's source will be published after its third-party audit completes.
- Signal introduced usernames in 2024, but a phone number is still needed to create an account.
How VoidSend's encryption works
Every message key is agreed with a hybrid of X25519 and ML-KEM-768, sealed with AES-256-GCM and signed with ML-DSA-65. Keys derive from your passkey, so nothing is backed up or uploaded. The full explanation is on the security page, and the reasoning behind post-quantum cryptography is in post-quantum messaging explained.
Other comparisons: VoidSend vs WhatsApp · VoidSend vs Telegram