[thadt]

Strong pre-shared keys will continue to remain secure, even against a quantum computer.

Wireguard, for example, provides the ability to add a pre-shared key for endpoints, which it mixes in during key exchange. Wireguard sessions collected under such a configuration should remain safe when attacked by a future quantum computer, assuming that the shared keys remain secret.

Pre-shared keys are just inconvenient to handle safely.

[Panino]

> Pre-shared keys are just inconvenient to handle safely.

You can transfer PSKs safely and easily with OpenSSH 9.0 (released 2022-04-08) or later, which uses [e-mail] as the default key exchange method.

[Gh0stRAT]

If your threat model includes someone with a quantum computer intercepting all of your traffic and storing it to decrypt later, you probably don't want to share your keys over a non-PQC channel unless you can guarantee that they haven't started eavesdropping on your traffic yet.

[thadt]

While sntrup761x25519-sha512 is a QC secure key exchange, sending a key over it doesn't count. It's not really a "pre-shared" key unless the sharing is done using organic, locally sourced sneakers. Unless FIPs, and then it's boots.