What is TLS?

TLS is what makes HTTPS secure: it encrypts the connection between your browser and a site so nobody on the path can read or change it. The old versions, TLS 1.0 and 1.1, were formally retired in 2021. TLS 1.2 is still safe when set up well, and TLS 1.3, published in 2018, removes the weak old options entirely and sets up a connection faster.

On the “My device” page, the “Connection encryption” row shows the TLS and HTTP versions of your connection to CheckNet, such as “TLSv1.3 over http/2”. If the version is older than 1.3, the row shows a warning.

Post-quantum key exchange

At the start of every connection, the browser and the site agree on a shared key. Today’s usual methods are safe against current computers, but a large quantum computer in the future could break them. The main risk is “harvest now, decrypt later”: someone records encrypted traffic today to open it years from now.

So browsers use a hybrid: the key is made with the familiar X25519 method and with ML-KEM at the same time, which the US standards institute NIST standardised in 2024. If one of the two is ever broken, the other still protects the connection. CheckNet shows this combination as X25519MLKEM768. Recent versions of Chrome, Edge and Firefox use it by default.

If it says “no” or TLS 1.2

1. Update your browser to the latest version, then close and reopen it.
2. Update your operating system too; some browsers, especially on iPhone and iPad, use the system’s own encryption.
3. If your antivirus or security software has an option like “HTTPS scanning” or “scan encrypted traffic”, know that it opens the connection in the middle and may fall back to an older version or method. Turn that option off for a moment and test again.
4. On a work or university network, traffic inspection devices can have the same effect. Compare with another network, such as your phone’s mobile data.
5. A VPN or proxy app that opens traffic can also be the cause; test once without it.

Does “no” for post-quantum key exchange mean the connection is unsafe today? No. It is still encrypted with strong methods; this row is only about protection against decryption in the distant future.

Check again with CheckNet

After each change, reload the “My device” page. The good result is “TLSv1.3” in the encryption row and “yes” in the post-quantum row. These rows show only your connection to CheckNet; other sites may not support post-quantum key exchange yet.