Doesn't look like it currently but we're definitely going to add FIPS and mesh support to nostr:npub1whtn0s68y3cs98zysa4nxrfzss5g5snhndv35tk5m2sudsr7ltms48r3ec in the future. Just waiting on a few key features to land in FIPS before we start on that work.

No. PsstPsst uses NIP-17 DMs built on NIP-4e, which separates the encryption key from the identity key, so it’s not compatible with most Nostr clients. The Bluetooth protocol is custom for now, but I plan to support it via FIPS in the future.