“Secure messaging has become almost a fundamental right for much of the global population. There is a pressing need to build quantum-secure solutions that mimic the functionality and security guarantee of the Signal protocol’s existing key components. The stakes are just too high not to do so.”Īdding post-quantum cryptography to the Signal protocol – considered the gold standard for establishing secure messaging between two parties – would not be without technical challenges. That’s why we are publishing our full analysis, research and solutions for how to protect secure instant messaging from the quantum threat.

However, the cryptographic problem underlying its security is known to be easily solvable by quantum computers, and any adversary harvesting current communications would easily be able to decrypt exchanged messages in the future. Thomas Prest, Lead Cryptography Researcher at PQShield said: “The Signal protocol is widely regarded as the gold standard for secure instant messaging. Adding post-quantum cryptography to the Signal protocol

Threat actors could already be gathering and storing encrypted messages today, with a view to decrypting them at a later date, with potentially devastating consequences. The issue is compounded by the prospect of a “harvest now, decrypt later” attack. But however secure these messaging apps are today, large-scale quantum computers will soon have the processing power to break the end-to-end encryption they rely on to keep messages private.

Over 2 billion people used WhatsApp in January 2022, and 40 million people used Signal. The widespread adoption of smartphones in the last decade has brought with it a meteoric rise in the use of secure messaging apps. The company is offering to license its end-to-end encrypted messaging IP to the Signal Foundation pro bono – if/when they plan to upgrade their system – to support the non-profit behind the free encrypted messaging app, Signal, in its mission to make secure communication accessible to everyone. PQShield published a white paper that lays out the quantum threat to secure end-to-end messaging and explains how post-quantum cryptography (PQC) can be added to the Signal secure messaging protocol to protect it from quantum attacks.