Signal vs WhatsApp vs iMessage: Are Your Messages Safe From Quantum Computers?
The Scorecard
| App | PQC status | Algorithm | Launch date |
|---|---|---|---|
| Signal | Shipped | PQXDH: X25519 + Kyber-1024 hybrid | Sept 19, 2023 |
| iMessage | Shipped | PQ3: hybrid ECDH + Kyber/ML-KEM | Feb 21, 2024 |
| Classical | X3DH only | N/A | |
| Telegram | Classical | MTProto | N/A |
| Wire | Partial | Working on PQC | In progress |
| Threema | Classical | Classical | N/A |
| Element (Matrix) | Partial | Olm/Megolm; PQC roadmap | In progress |
Signal PQXDH Details
Signal announced Post-Quantum Extended Diffie-Hellman (PQXDH) on September 19, 2023 via signal.org/blog/pqxdh/. It adds a post-quantum KEM (Kyber-1024) to the existing X3DH key agreement, so an attacker must break both X25519 and Kyber to recover session keys.
Deployment is incremental: initial version added to message-sending, then ratcheted through future sessions.
iMessage PQ3 Details
Apple announced iMessage PQ3 on February 21, 2024 via security.apple.com/blog/imessage-pq3/. It uses Kyber (now ML-KEM) public keys alongside classical ECDH. Rolled out in iOS 17.4, iPadOS 17.4, macOS 14.4, watchOS 10.4 in March 2024.
As of April 2026, WhatsApp continues to use the Signal-derived X3DH protocol without Post Quantum Cryptography extensions. Meta has communicated general interest in PQC but has not announced a WhatsApp launch date.
Telegram
Telegram's MTProto uses classical Diffie-Hellman. No public PQC roadmap as of April 2026. Secret Chats use additional end-to-end encryption but still classical.
Wire
Wire has communicated PQC roadmap but production default PQC is not yet confirmed as of April 2026.
Practical Recommendation
- For sensitive conversations, use Signal (PQC since Sept 2023) or iMessage (on supported Apple devices since March 2024).
- For WhatsApp-only relationships, understand the HNDL risk and plan migration.
- For Telegram, use only for low-sensitivity content until PQC ships.
Frequently Asked Questions
Is WhatsApp quantum-safe?
Not as of April 2026. Meta has not publicly announced a PQC launch date for WhatsApp. Use Signal or iMessage for sensitive communications.
Does iMessage PQC work between iPhone and Android?
No. iMessage PQ3 applies only to iMessage-to-iMessage conversations. RCS and SMS to Android do not get PQ3.
What is PQXDH?
Post-Quantum Extended Diffie-Hellman, Signal's hybrid key agreement combining X25519 with Kyber-1024. Launched September 19, 2023.
Is Signal sensor-stealing my conversations?
Signal is end-to-end encrypted with PQXDH. Signal servers see only encrypted bytes. This has been verified by multiple independent audits and Signal is fully open-source.
Sources
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Try QNSQYOriginally published at quantumsequrity.com/blog/signal-whatsapp-imessage-quantum-safe.