Signal has announced an upgrade to its end-to-end encryption (E2EE) protocol to protect its users from encryption-breaking attacks through quantum computers. Although Quantum computers are not yet powerful enough to be perceived as a threat for public-key cryptography, this does not mean they will not become a one in the future. Many organizations and companies are getting ready for the post-quantum era.
To advance quantum resistance for the Signal Protocol, Signal upgraded its Extended Triple Diffie-Hellman (X3DH) key agreement protocol to the Post-Quantum Extended Diffie-Hellman (PQXDH). The new protocol is already available to Signal app users in the latest versions. Both chat participants must update to the latest Signal software to enable this feature. This is said to elevate them far above all secure messaging apps.