Quantum Safety от Andrew E Scott

To protect yourself today from "store now decrypt later" attacks enabled by future quantum computers, you should use secure web sessions with quantum-safe algorithms. This add-on changes its icon to show a green tick if the main web page is safe, or a red stop sign if older, non quantum-safe algorithms are used. It does not currently assess whether other parts of the web page are accessed in a quantum-safe way.

The quantum-safe algorithms detected are common variants of the NIST standard ML-KEM (Module Lattice Key Encapsulation Mechanism), including hybrid variants. If a tick is shown, you can see which variant was detected by hovering the cursor over the icon.

This add-on works best when it is pinned to the toolbar so you can more readily see the icon changing.

Note that the permissions are required for the add-on to function. It needs to see all web sites so that it can show the right icon for them, it needs to access browser tabs to update the icon when the user changes between tabs, and it needs notifications to alert the user about missing permissions. No information about the web sites is retained beyond that, and it is deleted when the browser session ends.